CN111156990B - Space debris real-time astronomical positioning and photometry method based on automatic pointing determination - Google Patents
Space debris real-time astronomical positioning and photometry method based on automatic pointing determination Download PDFInfo
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Abstract
The invention discloses a space debris real-time astronomical positioning and photometry method based on automatic pointing determination, which comprises the following steps: generating a theoretical star map; stars and space debris stars; generating an actual measurement star map; matching the theoretical star map with the actual measurement star map; measuring the direction and the image plane rotation; searching fixed stars; the film model is optimized; calculating a photometric model; space debris astronomical positioning and photometry. The invention can automatically optimize the film model according to the size of the observation field, automatically measure the center pointing direction and the image surface rotation angle of the image according to the given time on the image, realize the automatic matching of the theoretical coordinate and the actual measurement coordinate of the fixed star, realize the automatic matching of the gray value of the fixed star and the theoretical star thereof on the image, and further realize the real-time astronomical positioning and photometry of the space debris.
Description
Technical Field
The invention relates to the technical field of space debris positioning, in particular to a space debris real-time astronomical positioning and photometry method based on automatic pointing determination.
Background
In many fields such as scientific research, military affairs and the like, space debris needs to be monitored, on one hand, the position and the change of the space debris in the sky at each observation moment are measured, the operation track of the space debris is determined, and therefore accurate information of the space debris is obtained. Based on the requirement, the accurate measurement of the space debris is a very important basic link, and the accurate measurement of the space debris is not available, and the track identification, the cataloging and the rail fixing of the space debris and the precise rail fixing of the space debris cannot be realized.
There are two methods for accurately measuring the position of space debris: the method comprises absolute positioning and relative positioning, wherein the absolute positioning is to realize space debris measurement by using a telescope axis system, is influenced by factors such as telescope axis system processing precision, atmospheric refraction correction precision, temperature deformation and the like, and does not depend on a background fixed star. The relative positioning is to realize the measurement of the space debris according to the relative position of the space debris and the background fixed star, the pointing accuracy of the telescope does not directly influence the measurement result, but under the condition that the pointing direction of the telescope and the installation error of the image surface are large, the difference between the theoretical coordinate of the fixed star on the image and the actually measured coordinate of the fixed star on the image is large, especially for the image with the error of the image surface, the error of the edge part is large, the given matching threshold cannot be met, so the matching failure of the theoretical star map and the actually measured star map of the fixed star is caused, and the relative positioning cannot.
There are also two methods for photometric accurate measurement of space debris: absolute measurement and relative measurement. The method comprises the following steps that a plurality of standard photometry calibration stars in different fields of view are utilized to obtain a photometry model, which is called an absolute measurement model and is also called absolute photometry; the light metering model obtained by using a plurality of light metering calibration stars in the same field of view is called as a relative measurement model, and is also called as relative light metering. In any light measuring mode, the method is based on the fact that actually measured gray scales of fixed stars and the matching with theoretical stars of fixed stars are successful, and the accurate temperature, relative humidity and atmospheric pressure of a measuring station are needed. Even in such a case, in an area of low elevation, the correction accuracy of the atmospheric refraction is affected, and the correction accuracy of the pointing error of the telescope is low.
Based on the defects of the existing astronomical positioning method, the invention provides a space target real-time astronomical positioning method based on automatic direction determination, which can automatically select a negative film model according to the size of an observation field, automatically determine the direction of the center of an image and the rotation angle of an image surface according to the given time and the direction of the center of the image without direction information input, and realize the automatic matching of a fixed star theoretical coordinate and an actually measured coordinate, thereby realizing the real-time astronomical positioning and photometry of space debris.
Disclosure of Invention
The invention aims to provide a space debris real-time astronomical positioning and photometry method based on automatic direction measurement, which can automatically select a negative film model according to the size of an observation field, automatically measure the center direction and the image surface rotation angle of an image according to the given time on the image, realize the automatic matching of a fixed star theoretical coordinate and an actually measured coordinate, realize the automatic matching of a fixed star gray value and a theoretical star thereof on the image, and further realize the real-time astronomical positioning and photometry of the space debris. For a telescope with a fixed station address (with precise astronomical longitude and latitude), the method reduces the requirement on the machining precision of a telescope axis, reduces the requirement on the installation and debugging of an external field of the telescope, reduces the requirement on the environmental temperature reference input of a survey station, and reduces the requirement on pointing calibration before observation. For a movable telescope, the method can automatically measure the zero point difference of two axes of the telescope and can also realize real-time astronomical positioning and relative photometry of space debris under the condition that pointing calibration of the telescope cannot be realized without precise astronomical longitude and latitude. More importantly, the method can realize high-precision astronomical positioning and relative photometry on a mobile station site without astronomical longitude and latitude (only geographical longitude and latitude).
To achieve the above object, with reference to fig. 1, the present invention provides a real-time astronomical positioning and light measuring method for space debris based on automatic pointing measurement, wherein the real-time astronomical positioning and light measuring method comprises the following steps:
s1: generating an astronomical positioning fixed star library and first index data for expressing self information of all fixed stars contained in the astronomical positioning fixed star library; generating a whole-day-area theoretical star map and second index data for expressing angular distance information between stars contained in the whole-day-area theoretical star map based on an astronomical positioning star library;
s2: receiving at least one frame of image comprising space debris and background stars, and obtaining star image information of the stars and the space debris on the image within a preset detection threshold; calculating to obtain the angular distance between any two fixed stars based on the obtained star image information of the fixed stars, and generating a fixed star actual measurement star map;
s3: according to the theoretical star map of the whole day region and the second index data, the upper and lower limits of the actually measured star map of the fixed star are determined, and the maximum angular distance is obtained
Minimum angular distance
Intermediate angular distance
Combined maximum angular distance
Minimum angular distance
Intermediate angular distance
According to a preset matching rule, calculating to obtain a plurality of fixed star planets which are contained in an actually measured fixed star atlas and are matched with a theoretical star atlas of an all-day area;
s4: calculating to obtain center pointing deviation, image surface rotation angle, negative film constant model and relative photometric model based on the successfully matched star image information;
wherein, the photometry model is:
wherein G isiThe gray value of the ith successfully matched star-star image after background subtraction,
is a theoretical star corresponding to the ith successfully matched star-star image, i is 1,2, …, N3，N3Is the total number of successfully matched star stars, and A and B are relative photometric model coefficients calculated by a least square method.
In a further embodiment, in step S2, the process of generating the measured star map of the fixed star includes the following steps:
selecting N from the image according to a given threshold1The star image of the fixed star is defined as a first candidate fixed star, the angular distance between any two first candidate fixed stars is obtained through calculation by combining the two-dimensional plane coordinates of the first candidate fixed star on the image and the focal length of the telescope, three first candidate fixed stars are selected to form a triangular star map, and a fixed star actual measurement star map is generated;
the angular distance between any two first candidate stars is calculated by adopting the following formula:
where f is the focal length of the telescope, (x)j,yj) Is the two-dimensional plane coordinate of the jth first candidate star, (x)k,yk) Is the two-dimensional plane coordinates of the kth first candidate star.
In a further embodiment, in step S1, the generating an astronomical positioning star base and the first index data for describing all star self information included in the astronomical positioning star base includes:
and storing the fixed stars in the whole day area of the given star and the like in a partitioning manner according to the increasing order of the right ascension and the increasing order of the declination, forming an index, and generating an astronomical positioning fixed star library and index data.
In a further embodiment, in step S1, the generating of the all-day-region theoretical star map and the second index data used for expressing the angular distance information between stars included in the all-day-region theoretical star map based on the astronomical positioning star library includes:
selecting a whole day region N according to a given star equal threshold2And the particle star elephant is defined as a second candidate star, the angular distance between any two second candidate stars is obtained through calculation by combining the right ascension and the declination of the second candidate stars, a triangular star map is formed by optionally selecting three second candidate stars according to a given angular distance threshold, a theoretical star map of the whole day area is generated, and the theoretical star map is sorted according to the angular distance of each triangle to generate corresponding index data.
In a further embodiment, in step S1, the angular distance between any two second candidate stars is calculated by the following formula:
wherein (alpha)u,δu) Is the right ascension and declination of the u-th second candidate star, (alpha)v,δv) Is the right ascension and declination, σ, of the v-th second candidate starc u,vIs the angular distance between the u-th and v-th second candidate stars.
In a further embodiment, in step S3, the step of calculating, according to a preset matching rule, a plurality of pieces of star stellar information which are included in the actually measured star atlas of the fixed star and are matched with the theoretical star atlas of the whole sky area includes the following steps:
s31: determining the upper and lower limits of the candidate star atlas according to the all-day area theoretical star atlas and the second index data, and acquiring the maximum angular distance
Minimum angular distance
Intermediate angular distance
S32: sequentially calculating the angular distance of a triangle formed by any three calibration stars i, j and k in the upper and lower boundaries, and setting the sequence of the calculated angular distances from large to small as
According to the following matching conditions, the calculated angular distance is calculated
Correspond to
Carrying out matching judgment until the matching is successful N3Particle fixed stars:
the jth scaling star and the kth scaling star satisfy the following formula:
the following formula is satisfied between any three i, j, k calibration stars:
wherein epsilon1And ε2All are preset angular distance thresholds;
in a further embodiment, in step S4, the process of calculating the center pointing deviation and the image plane rotation angle based on the information of the plurality of star planets successfully matched includes the following steps:
n for successful design matching3The two-dimensional plane coordinate of the particle fixed star on the image is (x)i,yi)，i＝1,2,…N3The corresponding theoretical two-dimensional plane coordinate is (X)i,Yi)，i＝1,2,…N3；
Calculating coefficients a, b, c, d, e and f by using a least square method according to the following formula, so as to obtain a center pointing deviation and an image plane rotation angle:
in a further embodiment, in step S4, the acquiring process of the negative film constant model includes the following steps:
combining the astronomical positioning fixed star library and the first index data, and according to the shooting information corresponding to the image and the whole-day star map pointing measurement result (alpha)p,δp) Retrieving relevant information of all fixed stars meeting a given star equal threshold in the field of view, wherein the relevant information of the fixed stars meeting the given star equal threshold comprises corresponding two-dimensional plane coordinate theoretical values (X, Y), right ascension and declination theoretical values (alpha)s,δs) Ideal coordinate theoretical value (xi)s,ζs) The M such as theoretical stars and the like sort the searched fixed stars according to the sequence from small to large of the theoretical stars and the like; wherein the ideal coordinates (ξ)s,ζs) The following formula is satisfied:
the shooting information corresponding to the image comprises shooting time of the image, pointing information, longitude and latitude of the measuring station, altitude of the measuring station, temperature of the measuring station, humidity of the measuring station, atmospheric pressure and given view field size;
combining the successfully matched N according to the size of the corresponding view field of the image3Two-dimensional plane coordinate (x) of particle fixed star on imagei,yi) And ideal coordinates
i＝1,2,…N3And calculating a constant model, automatically optimizing the film constant model according to the positioning accuracy of the fixed star, and automatically storing the optimized film constant model.
In a further embodiment, said performing constant model calculations comprises,
and (3) combining the number of successfully matched calibration stars, and respectively selecting a six-constant model, a twelve-constant model and a fourteen-constant model for constant model calculation, wherein:
the six-constant model corresponds to at least 3 calibration stars:
the twelve constant model corresponds to at least 6 calibration stars:
the fourteen-constant model corresponds to at least 7 calibration stars:
in a further embodiment, the real-time astronomical positioning method further comprises:
s5: according to the two-dimensional plane coordinate measured value (x) of the space debrisT,yT) Is adopted toThe following formula obtains the right ascension and declination (alpha) of the space debrisT,δT)：
Wherein (xi)T,ζT) Is the ideal coordinate of space debris, consisting ofT,yT) And substituting a six-constant model, a twelve-constant model or a fourteen-constant model to obtain the model.
Compared with the prior art, the technical proposal of the invention has the obvious beneficial effects that,
(1) the negative film model can be automatically optimized according to the size of an observation view field, the image center pointing direction and the image surface rotation angle are automatically measured according to the given time and the image center pointing direction on the image, and the automatic matching of the fixed star theoretical coordinate and the actual measurement coordinate is realized, so that the real-time astronomical positioning and photometry of space debris are realized.
(2) For a telescope with a fixed station address (with precise astronomical longitude and latitude), the method reduces the requirement on the machining precision of a telescope axis, reduces the requirement on the installation and debugging of an external field of the telescope, reduces the requirement on the environmental temperature reference input of a survey station, and reduces the requirement on pointing calibration before observation. For the movable telescope, the method can realize real-time astronomical positioning and relative photometry of space debris under the condition that pointing calibration of the telescope cannot be realized without precise astronomical longitude and latitude. Therefore, the method is a very good space debris real-time astronomical positioning and light measuring method.
(3) The method can realize high-precision astronomical positioning and relative photometry on a mobile station site without astronomical longitude and latitude (only geographical longitude and latitude), has good actual processing effect, and can be widely applied to the fields of scientific research and engineering.
(4) The computer system can give space debris astronomical positioning results, fixed star astronomical positioning results, pointing image plane rotation measuring results and fixed star retrieval results on the images in real time. The results are widely applied, for example, the results can be displayed by a display system, stored in a storage medium of a computer system, used for cataloging and precisely tracking the space debris, and corrected according to the pointing measurement result, so that the capturing and tracking success rate of the space debris can be improved.
It should be understood that all combinations of the foregoing concepts and additional concepts described in greater detail below can be considered as part of the inventive subject matter of this disclosure unless such concepts are mutually inconsistent. In addition, all combinations of claimed subject matter are considered a part of the presently disclosed subject matter.
The foregoing and other aspects, embodiments and features of the present teachings can be more fully understood from the following description taken in conjunction with the accompanying drawings. Additional aspects of the present invention, such as features and/or advantages of exemplary embodiments, will be apparent from the description which follows, or may be learned by practice of specific embodiments in accordance with the teachings of the present invention.
Drawings
The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. Embodiments of various aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
fig. 1 is a flow chart of the space debris real-time astronomical positioning and light measuring method based on automatic pointing determination of the present invention.
Detailed Description
In order to better understand the technical content of the present invention, specific embodiments are described below with reference to the accompanying drawings.
With reference to fig. 1, the present invention provides a real-time astronomical positioning and photometry method for space debris based on automatic pointing measurement, comprising the following steps:
s1: generating an astronomical positioning fixed star library and first index data for expressing self information of all fixed stars contained in the astronomical positioning fixed star library; and generating a whole-day-region theoretical star map and second index data for expressing the angular distance information between the stars contained in the whole-day-region theoretical star map based on the astronomical positioning star library.
S2: receiving at least one frame of image comprising space debris and background stars, and obtaining star image information of the stars and the space debris on the image within a preset detection threshold; and calculating to obtain the angular distance between any two fixed stars based on the acquired star image information of the fixed stars, and generating the actually measured star map of the fixed stars.
S3: according to the theoretical star map of the whole day region and the second index data, the upper and lower limits of the actually measured star map of the fixed star are determined, and the maximum angular distance is obtained
Minimum angular distance
Intermediate angular distance
Combined maximum angular distance
Minimum angular distance
Intermediate angular distance
And according to a preset matching rule, calculating to obtain a plurality of fixed star planets which are contained in the fixed star actual measurement star atlas and are matched with the all-day area theoretical star atlas.
S4: and calculating to obtain center pointing deviation, image surface rotation angle, negative film constant model and relative photometric model based on the information of a plurality of star planets successfully matched.
Wherein, the photometry model is:
wherein G isiIs that the ith matching is successfulThe gray value of the star-star image after deducting the background,
is a theoretical star corresponding to the ith successfully matched star-star image, i is 1,2, …, N3，N3Is the total number of successfully matched star stars, and A and B are relative photometric model coefficients calculated by a least square method.
Briefly, the technical scheme of the invention comprises the following working steps:
(1) and generating a theoretical star map.
(2) Stars and space debris stars.
(3) And generating an actual measurement star map.
(4) And matching the theoretical star map with the actual measurement star map.
(5) And measuring the direction and the image plane rotation.
(6) And (5) searching stars.
(7) The negative model is preferred.
(8) And (5) calculating a photometric model.
(9) Space debris astronomical localization.
In practical application, after acquiring star image information of stars and space debris on each frame of image through space target detection aiming at the collected continuous observation images, the 9 steps are sequentially adopted to acquire astronomical positioning and photometric data of the space debris. More optimally and more specifically describing the above steps as follows:
first, theoretical star map generation
And storing the stars in all-day regions of the given star and the like in a partitioning manner according to the increasing order of the right ascension and the increasing order of the declination, forming an index, and generating an astronomical positioning star database and first index data for searching the stars. Selecting a whole day region N according to a given star equal threshold2The star image of the particle stars calculates the angular distance between any two fixed stars by adopting the following formula according to the information of the right ascension and the declination of the fixed stars:
wherein (alpha)u,δu) Is the right ascension and declination of the u-th second candidate star, (alpha)v,δv) Is the right ascension and declination of the v second candidate star
And according to a given threshold, such as minimum and maximum angular distances, optionally selecting three stars to form a triangular star map, generating a theoretical star map of the whole sky area, and sorting according to the angular distance of each triangle. And generating a theoretical star atlas database of the whole day area and corresponding second index data for star atlas retrieval.
Second, fixed star and space debris astrology
According to the space debris detection method, star image information of stars and space debris on an image within a detection threshold is obtained, wherein the star image information comprises two-dimensional plane coordinates (x, y), the number of pixels, the gray sum, and the image is sorted according to the decreasing sequence of the number of pixels. Preferably, any space debris acquisition method in the prior art can be adopted to obtain star image information of stars and space debris within the detection threshold on the image. The left upper corner of the image is set as a coordinate origin (0, 0), the right side of the image is set as an x-axis increasing direction, the lower side of the image is set as a y-axis increasing direction, x is the distance between the position of the star in the image and the coordinate origin in the x-axis direction, and y is the distance between the position of the star in the image and the coordinate origin in the y-axis direction.
Third, actual measurement star map generation
According to a given threshold, selecting N1The focal length of the telescope is f according to the two-dimensional plane coordinates (x, y) of the star image of the fixed star. The angular distance between any two fixed stars is calculated by adopting the following formula, and three fixed stars are selected by people to form a triangular star map so as to generate an actual measurement star map of the fixed stars. Calculating the angular distance between any two first candidate stars by adopting the following formula:
wherein (x)j,yj) Is the two-dimensional plane coordinate of the jth second candidate star, (x)k,yk) Is the k second candidate starPlane coordinates.
Fourthly, matching the theoretical star map with the actual measurement star map
For any three calibration stars i, j, k on the image, the angular distance is formed in the order of magnitude
The triangles of (1) quickly realize the upper and lower boundaries n of the candidate star atlas according to the index of the theoretical star atlas, and the corresponding angular distances of the triangles in the upper and lower boundaries are in the order of magnitude
And (6) carrying out matching judgment.
Since f may not be too accurate, the relationship between the jth and kth calibration stars can still satisfy the following equation:
the following formula is satisfied between any three i, j, k calibration stars:
and
and fifthly, measuring the direction and the image plane rotation.
Suppose the matching is successful N3Fixed star, two-dimensional plane coordinate (x) of star on imagei,yi)，i＝1,2,…N3Theoretical two-dimensional planar coordinate (X) of a star imagei,Yi)，i＝1,2,…N3。
Calculating coefficients a, b, c, d, e and f by using a least square method according to the following formula, so as to obtain a center pointing deviation and an image plane rotation angle:
sixthly, searching stars.
According to the time corresponding to the image and the whole-day star map orientation measurement result (alpha)p,δp) The method comprises the steps of searching fixed star information which meets thresholds such as a given star and the like in a view field and comprises two-dimensional plane coordinate theoretical values (X, Y), right ascension and declination theoretical values (alpha)s,δs) Ideal coordinate theoretical value (xi)s,ζs) M such as theoretical stars and the like, and sequencing according to the increasing sequence of the theoretical stars and the like. The ideal coordinate (xi)s,ζs) The following formula is satisfied:
seventh, the negative film model is preferred.
According to the size of the corresponding field of view of the image, the matching is assumed to be successful N3Fixed star, two-dimensional plane coordinate (x) of star on imagei,yi) And ideal coordinates
i＝1,2,…N3. And (4) automatically optimizing the negative constant model according to the positioning precision of the fixed star by adopting the following six-constant, twelve-constant and fourteen-constant model calculation (the optimization is only needed once, and the optimization result is automatically stored).
Six constant model (need more than 3 calibration stars)
Twelve constant model (requiring more than 6 calibration stars)
Fourteen constant model (requiring more than 7 calibration stars)
Eight, photometric model calculation
Suppose the matching is successful N3The gray value of the particle star and the star image minus the background is GiAnd the corresponding theoretical star, etc. is Mi c，i＝1,2,…,N3. Relative photometric model coefficients a and B were obtained using the following formula using the least squares method:
Mi c＝Α+B log(Gi). LOG has 10 subscripts
And ninthly, astronomical positioning of the space debris.
According to the two-dimensional plane coordinate measured value (x) of the space debrisT,yT) The right ascension and declination (alpha) of the space debris are obtained using the following formulaT,δT)：
Wherein (xi)T,ζT) Is the ideal coordinate of space debris, consisting ofT,yT) And substituting a six-constant model, a twelve-constant model or a fourteen-constant model to obtain the model.
And the computer system provides space debris astronomical positioning and light measuring results, fixed star astronomical positioning and light measuring results, pointed image plane rotation measuring results and fixed star retrieval results on the image in real time according to the input data. The results can be displayed by a display system, stored in a storage medium of a computer system, used for cataloging, orbit determination and precise orbit determination of the space debris, and the forecast positions of the space debris can be corrected according to the pointing measurement result, so that the capturing and tracking success rate of the space debris can be improved; the method can be used for space debris identification, and can be used for evaluating the working state, the rotating state and the like of the attitude control space target.
In this disclosure, aspects of the present invention are described with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. Embodiments of the present disclosure are not necessarily defined to include all aspects of the invention. It should be appreciated that the various concepts and embodiments described above, as well as those described in greater detail below, may be implemented in any of numerous ways, as the disclosed concepts and embodiments are not limited to any one implementation. In addition, some aspects of the present disclosure may be used alone, or in any suitable combination with other aspects of the present disclosure.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the protection scope of the present invention should be determined by the appended claims.
Claims (9)
1. A space debris real-time astronomical positioning and photometry method based on automatic pointing determination is characterized by comprising the following steps of:
s1: generating an astronomical positioning fixed star library and first index data for expressing self information of all fixed stars contained in the astronomical positioning fixed star library; generating a whole-day-area theoretical star map and second index data for expressing angular distance information between stars contained in the whole-day-area theoretical star map based on an astronomical positioning star library;
s2: receiving at least one frame of image comprising space debris and background stars, and obtaining star image information of the stars and the space debris on the image within a preset detection threshold; calculating to obtain the angular distance between any two fixed stars based on the obtained star image information of the fixed stars, and generating a fixed star actual measurement star map;
s3: according to the theoretical star map of the whole day region and the second index data, the upper and lower limits of the actually measured star map of the fixed star are determined, and the maximum angular distance is obtained
Minimum angular distance
Intermediate angular distance
Combined maximum angular distance
Minimum angular distance
Intermediate angular distance
According to a preset matching rule, calculating to obtain a plurality of fixed star planets which are contained in an actually measured fixed star atlas and are matched with a theoretical star atlas of an all-day area;
s4: calculating to obtain center pointing deviation, image surface rotation angle, negative film constant model and photometric model based on the successfully matched star image information of a plurality of fixed stars;
wherein, the photometry model is:
wherein G isiThe gray value of the ith successfully matched star-star image after background subtraction,
is a theoretical star corresponding to the ith successfully matched star-star image, i is 1,2, …, N3，N3The total number of successfully matched star planets, and alpha and B are photometric model coefficients calculated by a least square method;
the real-time astronomical positioning method further comprises the following steps:
s5: actually measuring according to two-dimensional plane coordinates of space debrisValue (x)T,yT) The right ascension and declination (alpha) of the space debris are obtained using the following formulaT,δT)：
Wherein (xi)T,ζT) Is the ideal coordinate of space debris, consisting ofT,yT) And substituting a six-constant model, a twelve-constant model or a fourteen-constant model to obtain the model.
2. The method for real-time astronomical positioning and photometry of space debris based on automatic direction finding of claim 1, wherein in step S2, the process of generating the measured star map of stars comprises the steps of:
selecting N from the image according to a given threshold1The star image of the fixed star is defined as a first candidate fixed star, the angular distance between any two first candidate fixed stars is obtained through calculation by combining the two-dimensional plane coordinates of the first candidate fixed star on the image and the focal length of the telescope, three first candidate fixed stars are selected to form a triangular star map, and a fixed star actual measurement star map is generated;
the angular distance between any two first candidate stars is calculated by adopting the following formula:
where f is the focal length of the telescope, (x)j,yj) Is the two-dimensional plane coordinate of the jth first candidate star, (x)k,yk) Is the two-dimensional plane coordinates of the kth first candidate star.
3. The method for real-time astronomical localization and photometry of space debris based on automatic direction finding as claimed in claim 1, wherein the step S1 comprises generating an astronomical localization star database and first index data for describing self information of all stars included in the astronomical localization star database,
and storing the fixed stars in the whole day area of the given star and the like in a partitioning manner according to the increasing order of the right ascension and the increasing order of the declination, forming an index, and generating an astronomical positioning fixed star library and index data.
4. The method for real-time astronomical localization and photometry of space debris based on automatic direction finding as claimed in claim 1, wherein in step S1, the method for real-time astronomical localization and photometry of space debris based on automatic direction finding generates a full-sky theoretical star map and second index data for expressing information on angular distances between stars included in the full-sky theoretical star map,
selecting a whole day region N according to a given star equal threshold2And the particle star elephant is defined as a second candidate star, the angular distance between any two second candidate stars is obtained through calculation by combining the right ascension and the declination of the second candidate stars, a triangular star map is formed by optionally selecting three second candidate stars according to a given angular distance threshold, a theoretical star map of the whole day area is generated, and the theoretical star map is sorted according to the angular distance of each triangle to generate corresponding index data.
5. The method for real-time astronomical localization and photometry of space debris based on automatic direction finding of claim 4, wherein in step S1, the angular distance between any two second candidate stars is calculated by the following formula:
wherein (alpha)u,δu) Is the right ascension and declination of the u-th second candidate star, (alpha)v,δv) Is the right ascension and declination of the vth second candidate star,
is the angular distance between the u-th and v-th second candidate stars.
6. The method for real-time astronomical positioning and photometry of space debris based on automatic direction finding as claimed in claim 1, wherein the step S3 of calculating and obtaining a plurality of star stellar information matched with the theoretical astrogram in the whole sky area contained in the actually measured star atlas according to the preset matching rules comprises the steps of:
s31: determining the upper and lower limits of the candidate star atlas according to the all-day area theoretical star atlas and the second index data, and acquiring the maximum angular distance
Minimum angular distance
Intermediate angular distance
S32: sequentially calculating the angular distance of a triangle formed by any three calibration stars i, j and k in the upper and lower boundaries, and setting the sequence of the calculated angular distances from large to small as
According to the following matching conditions, the calculated angular distance is calculated
Correspond to
Carrying out matching judgment until the matching is successful N3Particle fixed stars:
the jth scaling star and the kth scaling star satisfy the following formula:
the following formula is satisfied between any three i, j, k calibration stars:
wherein epsilon1And ε2All are preset angular distance thresholds;
7. the method for real-time astronomical positioning and photometry of space debris based on automatic pointing direction determination of claim 1, wherein the step S4 of calculating the central pointing deviation and the image plane rotation angle based on several star image information successfully matched comprises the following steps:
n for successful design matching3The two-dimensional plane coordinate of the particle fixed star on the image is (x)i,yi)，i＝1,2,…N3The corresponding two-dimensional plane coordinate theory value is (X)i,Yi)，i＝1,2,…N3；
Calculating coefficients a, b, c, d, e and f by using a least square method according to the following formula, so as to obtain a center pointing deviation and an image plane rotation angle:
8. the method for real-time astronomical positioning and photometry of space debris based on automatic pointing determination according to claim 1, wherein the acquiring of the negative constant model in step S4 comprises the steps of:
combining the astronomical positioning fixed star library and the first index data, and according to the shooting information corresponding to the image and the whole-day star map pointing measurement result (alpha)p,δp) Retrieving relevant information of all fixed stars meeting a given star threshold in the field of view, wherein the relevant information of the fixed stars meeting the given star threshold comprises a two-dimensional plane corresponding to the fixed starsTheoretical values of surface coordinates (X, Y), right ascension and declination (alpha)s,δs) Ideal coordinate theoretical value (xi)s,ζs) The M such as theoretical stars and the like sort the searched fixed stars according to the sequence from small to large of the theoretical stars and the like; wherein the ideal coordinate theoretical value (ξ)s,ζs) The following formula is satisfied:
the shooting information corresponding to the image comprises shooting time of the image, pointing information, longitude and latitude of the measuring station, altitude of the measuring station, temperature of the measuring station, humidity of the measuring station, atmospheric pressure and given view field size;
combining the successfully matched N according to the size of the corresponding view field of the image3Two-dimensional plane coordinate (x) of particle fixed star on imagei,yi) And ideal coordinates
And (4) constant model calculation is carried out, the negative constant model is automatically optimized according to the positioning precision of the fixed star, and the optimized negative constant model is automatically stored.
9. The method of claim 8, wherein the performing constant model calculations comprises,
and (3) combining the number of successfully matched calibration stars, and respectively selecting a six-constant model, a twelve-constant model and a fourteen-constant model for constant model calculation, wherein:
the six-constant model corresponds to at least 3 calibration stars:
the twelve constant model corresponds to at least 6 calibration stars:
the fourteen-constant model corresponds to at least 7 calibration stars:
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