CN104977000A - Middle/high-orbit constellation inter-satellite photographic observation sensor and inter-satellite angular distance measuring algorithm thereof - Google Patents

Abstract

The invention provides a middle/high-orbit constellation inter-satellite photographic observation sensor. The middle/high-orbit constellation inter-satellite photographic observation sensor comprises an optical system, an imaging unit and a data processing unit. An inter-satellite angular distance measuring method comprises the following steps: S1, mounting the middle/high-orbit constellation inter-satellite photographic observation sensor on an observation satellite, and observing a target satellite and a background fixed star by utilizing the optical system; S2, carrying out stellar map imaging on the target satellite and the background fixed star by the imaging unit, and carrying out filtering and noise reduction; S3, identifying the target satellite and the background fixed star by the data processing unit, and completing extraction for barycentric coordinates of star points; S4, calculating by the triangle principle to obtain the angular distance between a connection line from the observation satellite to the target satellite and a connection line from the observation satellite to the background fixed star. The middle/high-orbit constellation inter-satellite photographic observation sensor is compact in integral structure and high in integration, accurate inter-satellite angular distance information is provided for long-term and autonomous navigation of the existing navigation constellation, influences of accumulative errors caused by integral rotation of the constellation are accurately determined and eliminated, and absolute orientation of space and long-term high-accuracy autonomous orbit determination of the navigation constellation are effectively realized.

Description

Angular distance Measurement Algorithm between camera observation sensor and star thereof between middle high rail constellation star

Technical field

To the present invention relates in one camera observation sensor between high rail constellation star, and angular distance Measurement Algorithm between the star utilizing this sensor to realize.

Background technology

For ensure when land station lays limited, navigation constellation still can steady and continuous navigation information is provided, navigation constellation must possess the autonomous operation ability of long period.Constellation autonomous orbit determination is the prerequisite of constellation autonomous operation, but when traditional employing H_2O maser carries out constellation autonomous orbit determination, owing to not having outside reference, thus can bring immesurable problem.

Be considerable based on angular distance information to constellation integral-rotation, the basis of H_2O maser increases direction finding message between star (angular distance information), accurately can determine and eliminate the cumulative errors impact that constellation integral-rotation brings.After increasing Crosslink orientation observation information, in satellite transit independence, constellation integral-rotation ornamental etc., compared to other means, there is clear superiority, effectively can solve navigation constellation space absolute orientation, and then realize the long-term high-precision independent orbit determination of navigation constellation, realize the long-term autonomous operation of navigation constellation.

Based on above-mentioned, therefore the present invention to propose in one between high rail constellation star angular distance Measurement Algorithm between camera observation sensor and star thereof.

Summary of the invention

To the object of this invention is to provide in one between high rail constellation star angular distance Measurement Algorithm between camera observation sensor and star thereof, compact overall structure, integrated level is high, long-term autonomous operation for existing navigation constellation provides angular distance information between accurate star, accurately determine and eliminate the cumulative errors impact that constellation integral-rotation brings, effectively solving navigation constellation space absolute orientation and long-term high-precision independent orbit determination.

For achieving the above object, to the invention provides in one camera observation sensor between high rail constellation star, it comprises: optical system, observes the background fixed star in target satellite and field of view; Image-generating unit, it is arranged on the front end of described optical system, the throw light of receiving optics, carries out imaging to the target satellite had compared with poor optical properties with the background fixed star with stronger optical characteristics; Data processing unit, it is connected with described image-generating unit, receive the high-quality image information that image-generating unit obtains, the asterism center-of-mass coordinate of target satellite and background fixed star is extracted, and is resolved the angular distance obtained between observation satellite to the line direction and observation satellite to background fixed star line of target satellite by Triangle Principle.

Described optical system adopts refraction-reflection long-focal distance optical system, catadioptric by secondary, target satellite and background fixed star is imaged on image-generating unit.

Described optical system comprises: primary mirror, is primary event mirror, adopts secondary aspherical mirror, and is fixed by supported at three point mode; Secondary mirror is secondary reflection mirror, adopts secondary aspherical mirror, is arranged in sensor and can receives and reflect the position of the reflection ray of primary mirror; Compensating glass, is arranged on the position of the reflection ray that can receive secondary mirror in sensor.

Described primary mirror is revolution symmetrical secondary aspheric mirror; Described secondary mirror is quadric surface convex reflecting mirror; Described compensating glass is the combined lens of concave-convex lens.

Described image-generating unit receives the throw light through compensating glass, and this image-generating unit adopts cmos detector.

Angular distance measuring method between the star that the present invention also provides camera observation sensor between a kind of middle high rail constellation star, comprises following steps:

S1, camera observation sensor between middle high rail constellation star to be arranged on observation satellite, and to utilize the background fixed star in optical system 1 pair of target satellite and field of view to observe;

S2, image-generating unit carry out the imaging of starry sky image to target satellite and background fixed star, and carry out filtering process to the noise in the starry sky image after imaging;

S3, data processing unit identify target satellite and background fixed star, complete the extraction of the asterism center-of-mass coordinate of target satellite and background fixed star;

S4, on the basis of the asterism center-of-mass coordinate of the target satellite extracted and background fixed star, data processing unit resolves the angular distance obtained between observation satellite to the line and observation satellite to background fixed star line of target satellite by Triangle Principle.

In described S2, Gaussian filter is adopted to carry out filtering process to starry sky image.

In described S3, specifically comprise following steps:

S31, by the stellar target of target satellite or background fixed star and background separation, to be realized by starry sky image thresholding method;

S32, a certain single stellar target of target satellite or background fixed star to be separated with other stellar targets, to be communicated with domain method by starry sky image and to realize, the starry sky image after S31 segmentation uses and is communicated with domain method, target satellite and background fixed star are identified;

S33, target satellite or background fixed star are carried out to the calculating of asterism center-of-mass coordinate.

In described S32, specifically comprise following steps:

S321, four connection prejudgementing criteria analysis are carried out to the starry sky image of binaryzation, obtain position and its boundary rectangle of stellar target; Carrying out region segmentation to being communicated with the starry sky image after analyzing, making in each connected region, to there is a stellar target, thus obtaining the image L (x, y) after connected area segmentation;

S322, target satellite to be identified, utilize kinetic characteristic to distinguish target satellite and fixed star, because target satellite keeps static in the starry sky image of successive frame, thus can target satellite be identified by the starry sky image of comparison successive frame;

S323, fixed star to be identified, adopt triangle algorithm to realize.

In described S4, by corresponding for the asterism center-of-mass coordinate of target satellite or background fixed star in the imaging plane coordinate system of observation satellite, and according to triangle geometric relationship and triangle cosine formula calculate observation satellite to the line of target satellite and observation satellite to the line of background fixed star between angular distance.

In sum, angular distance Measurement Algorithm between camera observation sensor and star thereof between middle high rail constellation star provided by the present invention, compared with prior art, have the following advantages and beneficial effect: compact overall structure, integrated level is high, by adopting a set of high resolving power long-focal distance optical system, a set of high sensitivity image-generating unit and a set of high accuracy data processing unit, for traditional introduces direction finding message (angular distance information) between star based on H_2O maser orbit determination algorithm, accurately can determine and eliminate the cumulative errors impact that constellation integral-rotation brings, in independence, the aspects such as constellation integral-rotation ornamental have clear superiority.Effectively can solve navigation constellation space absolute orientation, and then realize the long-term high-precision independent orbit determination of navigation constellation, for the long-term autonomous operation realizing navigation constellation provides accurate metrical information.

Accompanying drawing explanation

Fig. 1 be in the present invention in the structural representation of camera observation sensor between high rail constellation star;

Fig. 2 be in the present invention between high rail constellation star camera observation sensor star between the process flow diagram of angular distance measuring method;

Fig. 3 is the process flow diagram of the stellar target recognition methods in the present invention;

Fig. 4 A is four connection criterion schematic diagram, and Fig. 4 B is eight connectivity criterion schematic diagram;

Fig. 5 is the angular distance observation schematic diagram in the present invention.

Embodiment

Below in conjunction with Fig. 1 ~ Fig. 5, describe a preferred embodiment of the present invention in detail.

As shown in Figure 1, be camera observation sensor between rail constellation star high in one provided by the invention, it comprises: high-resolution optical system 1, observes the background fixed star in target satellite and field of view; Highly sensitive image-generating unit 2, it is arranged on the front end of described optical system 1, the throw light of receiving optics 1, carries out imaging to the target satellite had compared with poor optical properties with the background fixed star with stronger optical characteristics; High-precision data processing unit 3, it is connected with described image-generating unit 2, receive the high-quality image information that image-generating unit 2 obtains, the asterism center-of-mass coordinate of target satellite and background fixed star is extracted, and is resolved the angular distance obtained between observation satellite to the line direction and observation satellite to background fixed star line of target satellite by Triangle Principle.

Described optical system 1 adopts refraction-reflection long-focal distance optical system, catadioptric by secondary, target satellite and background fixed star is imaged on image-generating unit 2.Concrete, described optical system 1 comprises: primary mirror 101, is primary event mirror, adopts secondary aspherical mirror, and is fixed by supported at three point mode, for reduce optical correction eyeglass aberration, improve observation quality, realize lightweight target; Secondary mirror 102 is secondary reflection mirror, adopts secondary aspherical mirror, is arranged in sensor and can receives and reflect the position of the reflection ray of primary mirror 101; Compensating glass 103, is arranged on the position of the reflection ray that can receive secondary mirror 102 in sensor, is used for eliminating aberration, aberration etc., improves image quality.

Described primary mirror 101 is revolution symmetrical secondary aspheric mirror.

Described secondary mirror 102 is quadric surface convex reflecting mirror.

Described compensating glass 103 is the combined lens of concave-convex lens.

Described image-generating unit 2 receives the throw light through compensating glass 103, and this image-generating unit 2 adopts has highly sensitive CMOS (Complementary Metal-Oxide-Semiconductor, complementary metal oxide semiconductor (CMOS)) detector.The two-way carrying out picture dot on the basis of existing technology reads, two-way independently amplifies, carry out digital-to-analog conversion respectively again, every road exports the digital picture of 11bit, then the 11bit Image Reconstruction that two-way exports becomes the high-dynamics image of 16bit, effectively can realize the detection to weak optical target, and effectively can suppress the reading noise of picture dot.

As shown in Figure 2, angular distance measuring method between the star that the present invention also provides camera observation sensor between a kind of middle high rail constellation star, comprises following steps:

S1, camera observation sensor between middle high rail constellation star to be arranged on observation satellite, and to utilize the background fixed star in optical system 1 pair of target satellite and field of view to observe;

S2, image-generating unit 2 pairs of target satellites and background fixed star carry out the imaging of starry sky image, and carry out filtering process to the noise in the starry sky image after imaging;

S3, data processing unit 3 pairs of target satellites and background fixed star identify, complete the extraction of the asterism center-of-mass coordinate of target satellite and background fixed star;

S4, on the basis of the asterism center-of-mass coordinate of the target satellite extracted and background fixed star, data processing unit 3 resolves the angular distance obtained between observation satellite to the line direction and observation satellite to background fixed star line of target satellite by Triangle Principle, and carries out fusion treatment to angular distance information between star.

In described S2, due to the mainly Gaussian noise of the noise in the starry sky image after imaging, Gaussian filter is therefore adopted to carry out filtering process to starry sky image.Gaussian filter is that a class selects the linear smoothing filter of weights according to the shape of Gaussian function, and therefore it is very effective for suppressing the Gaussian noise of Normal Distribution.

Further, the specific operation process of described Gaussian filter is: use each pixel in a template scanning starry sky image, the pixel weighted mean gray-scale value in the neighborhood utilizing template to determine is to replace the value of template center's pixel.Because certain pixel in any piece image is not only isolated, the pixel that it and surrounding are faced within territory has relation.So adopt and face territory co-operate with it, several territory of facing adds that this pixel constitutes a template, faces domain operation template operation to entire image.Related operation or convolution algorithm is utilized to realize result.

In the present embodiment, adopt Gaussian template to carry out filtering to each pixel in starry sky image, this Gaussian template obtains by adopting two-dimensional Gaussian function.Concrete, described Gaussian template is:

$\frac{1}{16}\left[\begin{array}{ccc}{k}_{11}=1& k_{12}=2& k_{13}=1\\ k_{21}=2& k_{22}=4& k_{23}=2\\ k_{31}=1& k_{32}=2& k_{33}=1\end{array}\right];$

The intermediate value of this Gaussian template is expressed as central element, namely will carry out the pixel element processed, and after calculation process, the pixel value of this point becomes:

$g(x,y)=\frac{1}{16}\underset{i=1}{\overset{3}{\Σ}}\underset{j=1}{\overset{3}{\Σ}}{k}_{ij}f(x_i,y_j);$

In formula, k _ijrepresent the coefficient that each gray scale point should be multiplied by; F (x _i, y _j) represent the gray-scale value that each gray scale point is corresponding.Through described Gaussian template, filtering process is carried out to starry sky image, the noise smoothing that can will exist in starry sky image, thus reach the object of noise decrease.

As shown in Figure 3, in described S3, specifically following steps are comprised:

S31, by the stellar target of target satellite or background fixed star and background separation, to be realized by starry sky image thresholding method;

S32, a certain single stellar target of target satellite or background fixed star to be separated with other stellar targets, to be communicated with domain method by starry sky image and to realize, the starry sky image after S31 segmentation uses and is communicated with domain method, target satellite and background fixed star are identified;

S33, target satellite or background fixed star are carried out to the calculating of asterism center-of-mass coordinate.

In described S31, according to prioris such as the signal characteristics of known stellar target, thresholding method not only can be used target satellite and background separation, filtering part can also cross bright or excessively dark fixed star.In the present embodiment, adopt the iterative threshold segmentation method relevant to the grey level histogram feature of starry sky image, concrete calculation procedure is:

S311, Gray Histogram feature according to starry sky image, obtain bimodal gray-scale value P ₁and P ₂, determine initial segmentation threshold value T ₀:

$T_0=\frac{P_1+P_2}{2};$

S312, to gray-scale value 0 to T ₀between pixel process, by gray-scale statistical, obtain ground unrest average and estimate of variance

$\widehat{\mathrm{\&mu;}}=\stackrel{\&OverBar;}{I}=\frac{1}{n}\underset{g(x,y)<T_0}{\&Sigma;}g(x,y);$

${\widehat{\mathrm{\&sigma;}}}^2=\frac{1}{n}\underset{g(x,y)}{\&Sigma;}g(x,y)-\stackrel{\&OverBar;}{I};$

In formula, g (x, y) represents the gray-scale value of pixel, and n represents that gray-scale value is positioned at 0 to T ₀between pixel quantity;

The ground unrest average that S313, basis calculate and estimate of variance determine new segmentation threshold, reduce with the probability making background pixel label unjustifiably as object pixel;

$\mathrm{\&alpha;}\left(T\right)=\underset{T}{\overset{\mathrm{\&infin;}}{\&Integral;}}p\left(x\right)dx;$

$p\left(x\right)=\frac{1}{\mathrm{\&sigma;}\sqrt{2\mathrm{\&pi;}}}{e}^{-\frac{{(x-\mathrm{\&mu;})}^2}{2{\mathrm{\&sigma;}}^2}};$

In formula, the probability density function that p (x) is ground unrest; T is the quantile Z of normal distribution α _α;

S314, in order to obtain higher segmentation precision, usually choosing a very little α (T), returning in S311, using the T that tries to achieve again as initial segmentation threshold value, again perform S311 ~ S313.So repeated multiple times, through iteration optimization repeatedly, using the segmentation threshold tended towards stability finally obtained as optimal segmenting threshold, and then obtain the image T (x, y) after Threshold segmentation.

In described S32, specifically comprise following steps:

S321, connectivity analysis is carried out to the starry sky image of binaryzation, obtain position and its boundary rectangle of stellar target; After connectivity analysis and region segmentation, think to there is a stellar target in each connected region, thus obtain the image L (x, y) after connected area segmentation;

According to the shape of stellar target, it generally can be divided into convex and spill two kinds, the asterism of the stellar target mentioned in the present invention belongs to convex target, therefore be applicable to adopting as shown in Figure 4 A four to be communicated with criterion to analyze, another spill target is then generally applicable to adopting eight connectivity criterion as shown in Figure 4 B to analyze;

S322, target satellite to be identified, according to the optical characteristics of known target satellite and the kinetic characteristic of target satellite and fixed star, utilize kinetic characteristic to distinguish target satellite asterism and fixed star asterism; Because target satellite almost keeps static in sequence starry sky image, therefore target satellite can be identified by the starry sky image of comparison successive frame;

S323, identify fixed star, fixed star recognition technology determines the gordian technique of fixed star, and recognition result directly affects the calculating of final angular distance information; Be adopt triangle algorithm to realize fixed star identification in the present embodiment, the angular distance that this algorithm Main Basis star is right and magnitude form multiple star group, thus reach identifying purpose; Need to follow certain criterion when selecting star group: the star 1) trying not to select to drop on field of view edge, because this star probably causes interference to matching algorithm, thus is easy to cause error hiding; 2) star as coupling can be selected in visual field should to be no less than 3; 3) star of the preferably image-generating unit energy better extract of the star in selected star group; 4) star in selected star group is preferably comparatively close to; 5) preferably adopt comparatively accurate star angular distance, and reduce the dependence to magnitude as far as possible;

Based on above-mentioned, following steps are comprised to the flow process that fixed star identifies:

A. in visual field, select the brightest star s1 as primary;

B. in the inner and outer ring radius (r1, r2) of primary s1, select two the brightest star s2 and s3 as identification companion star; S1, s2, s3 are arranged counterclockwise to adopt right-hand rule to ensure;

C. formed triangle with s1, s2, s3, calculated angular distance between any two; Three limits (i.e. three angular distance values) of diabolo carry out pattern match with certain error threshold ζ in navigation star database;

D. analyze matching result: a) do not have corresponding triangle pattern to match in navigation star database, so then using the secondary bright star in visual field as primary s1, and the process repeating above A ~ C is mated again; B) have unique triangle pattern to match in navigation star database, then the match is successful, and identification s1 is fixed star; C) there is plural triangle pattern to match in navigation star database, then select the brightest star s4 in the common factor of the annulus formed at the inner and outer ring radius of s1, s2, with s1, s2, s4, formation triangle, in navigation star database, re-start coupling;

E. repeat above process, until again without bright star in visual field, then complete the identification of institute's any stars.

In described S33, complete on the basis to target satellite and the identification of background fixed star, calculate the asterism center-of-mass coordinate of target satellite and background fixed star, in the present embodiment, the computing method of the target asterism barycenter be similar in Gaussian distribution for gray feature or energy distribution are:

$x=\frac{\underset{i=1}{\overset{n}{\&Sigma;}}{x}_{i}L(x_i,y_i)}{\underset{i=1}{\overset{n}{\&Sigma;}}{L}^2(x_i,y_i)};$

$y=\frac{\underset{i=1}{\overset{n}{\&Sigma;}}{y}_{i}L(x_i,y_i)}{\underset{i=1}{\overset{n}{\&Sigma;}}{L}^2(x_i,y_i)}.$

As shown in Figure 5, in described S4, suppose observation satellite i to be provided with camera observation sensor between middle high rail constellation star provided by the present invention, it carries out imaging observation to target satellite j and fixed star A; Can try to achieve the asterism center-of-mass coordinate of target satellite j and fixed star A at observation satellite i according to above-mentioned S1 ~ S3, the rectangular coordinate of its correspondence in the imaging plane coordinate system of observation satellite i is respectively P ₁(x ₁, y ₁, 0) and P ₂(x ₂, y ₂, 0), in known image space coordinate system, optical centre coordinate is that (0,0, f), f is the focal length of camera observation sensor optical lens between star to S again; According to triangle geometric relationship, obtain:

$\{\begin{array}{c}{P}_1=\sqrt{x_1^2+y_1^2+f^2}\\ P_2=\sqrt{x_2^2+y_2^2+f^2}\end{array};$

According to triangle cosine formula, obtain:

P ₁P ₂ ²＝P ₁S ²+P ₂S ²-P ₁S·P ₂S cos∠P ₁SP ₂；

Calculate the angular distance observed quantity between the line of observation satellite i to target satellite j and the line of observation satellite i to background fixed star A:

$\begin{array}{c}\&angle;P_1{\mathrm{SP}}_2=\arccos \frac{P_1{S}^2+P_2{S}^2-P_1{P_2}^2}{P_{1}S\&CenterDot;P_{2}S}\\ =\arccos \frac{\left(x_1^2+y_1^2+f^2\right)+\left(x_2^2+y_2^2+f^2\right)-{\left(x_1-x_2\right)}^2+{\left(y_1-y_2\right)}^2}{\sqrt{x_1^2+y_1^2+f^2}\sqrt{x_2^2+y_2^2+f^2}}\\ =\arccos \frac{\left(f^2+x_1{x}_2+y_1{y}_2\right)}{\sqrt{x_1^2+y_1^2+f^2}\sqrt{x_2^2+y_2^2+f^2}}\end{array}.$

In sum, angular distance Measurement Algorithm between camera observation sensor and star thereof between middle high rail constellation star provided by the present invention, compared with prior art, have the following advantages and beneficial effect: compact overall structure, integrated level is high, by adopting a set of high resolving power long-focal distance optical system, a set of high sensitivity image-generating unit and a set of high accuracy data processing unit, for traditional introduces direction finding message (angular distance information) between star based on H_2O maser orbit determination algorithm, accurately can determine and eliminate the cumulative errors impact that constellation integral-rotation brings, in independence, the aspects such as constellation integral-rotation ornamental have clear superiority.Effectively can solve navigation constellation space absolute orientation, and then realize the long-term high-precision independent orbit determination of navigation constellation, for the long-term autonomous operation realizing navigation constellation provides accurate metrical information.

Although content of the present invention has done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple amendment of the present invention and substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.

Claims (10)

1. a camera observation sensor between high rail constellation star in, is characterized in that, comprise:

Optical system (1), observes the background fixed star in target satellite and field of view;

Image-generating unit (2), it is arranged on the front end of described optical system (1), the throw light of receiving optics (1), carries out imaging to the target satellite had compared with poor optical properties with the background fixed star with stronger optical characteristics;

Data processing unit (3), it is connected with described image-generating unit (2), receive the high-quality image information that image-generating unit (2) obtains, the asterism center-of-mass coordinate of target satellite and background fixed star is extracted, and is resolved the angular distance obtained between observation satellite to the line direction and observation satellite to background fixed star line of target satellite by Triangle Principle.

2. camera observation sensor between high rail constellation star in as claimed in claim 1, it is characterized in that, described optical system (1) adopts refraction-reflection long-focal distance optical system, catadioptric by secondary, target satellite and background fixed star is imaged on image-generating unit (2).

3. camera observation sensor between high rail constellation star in as claimed in claim 2, it is characterized in that, described optical system (1) comprises:

Primary mirror (101) is primary event mirror, adopts secondary aspherical mirror, and is fixed by supported at three point mode;

Secondary mirror (102) is secondary reflection mirror, adopts secondary aspherical mirror, is arranged in sensor and can receives and reflect the position of the reflection ray of primary mirror (101);

Compensating glass (103), is arranged in sensor the position of the reflection ray that can receive secondary mirror (102).

4. camera observation sensor between high rail constellation star in as claimed in claim 3, it is characterized in that, described primary mirror (101) is revolution symmetrical secondary aspheric mirror; Described secondary mirror (102) is quadric surface convex reflecting mirror; The combined lens that described compensating glass (103) is concave-convex lens.

5. camera observation sensor between high rail constellation star in as claimed in claim 3, it is characterized in that, described image-generating unit (2) receives the throw light through compensating glass (103), and this image-generating unit (2) adopts cmos detector.

6. between high rail constellation star camera observation sensor star between an angular distance measuring method, it is characterized in that, comprise following steps:

S1, camera observation sensor between middle high rail constellation star to be arranged on observation satellite, and to utilize optical system (1) to observe the background fixed star in target satellite and field of view;

S2, image-generating unit (2) carry out the imaging of starry sky image to target satellite and background fixed star, and carry out filtering process to the noise in the starry sky image after imaging;

S3, data processing unit (3) identify target satellite and background fixed star, complete the extraction of the asterism center-of-mass coordinate of target satellite and background fixed star;

S4, on the basis of the asterism center-of-mass coordinate of the target satellite extracted and background fixed star, data processing unit (3) resolves the angular distance obtained between observation satellite to the line and observation satellite to background fixed star line of target satellite by Triangle Principle.

7. angular distance measuring method between star as claimed in claim 6, is characterized in that, in described S2, adopts Gaussian filter to carry out filtering process to starry sky image.

8. angular distance measuring method between star as claimed in claim 6, is characterized in that, in described S3, specifically comprise following steps:

S31, by the stellar target of target satellite or background fixed star and background separation, to be realized by starry sky image thresholding method;

S32, a certain single stellar target of target satellite or background fixed star to be separated with other stellar targets, to be communicated with domain method by starry sky image and to realize, the starry sky image after S31 segmentation uses and is communicated with domain method, target satellite and background fixed star are identified;

S33, target satellite or background fixed star are carried out to the calculating of asterism center-of-mass coordinate.

9. angular distance measuring method between star as claimed in claim 8, is characterized in that, in described S32, specifically comprise following steps:

S321, four connection prejudgementing criteria analysis are carried out to the starry sky image of binaryzation, obtain position and its boundary rectangle of stellar target; Carrying out region segmentation to being communicated with the starry sky image after analyzing, making in each connected region, to there is a stellar target, thus obtaining the image after connected area segmentation ;

S322, target satellite to be identified, utilize kinetic characteristic to distinguish target satellite and fixed star, because target satellite keeps static in the starry sky image of successive frame, thus can target satellite be identified by the starry sky image of comparison successive frame;

S323, fixed star to be identified, adopt triangle algorithm to realize.

10. angular distance measuring method between star as claimed in claim 6, it is characterized in that, in described S4, by corresponding for the asterism center-of-mass coordinate of target satellite or background fixed star in the imaging plane coordinate system of observation satellite, and according to triangle geometric relationship and triangle cosine formula calculate observation satellite to the line of target satellite and observation satellite to the line of background fixed star between angular distance.