CN107945229A - Fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument - Google Patents
Fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument Download PDFInfo
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Abstract
The invention discloses a kind of fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument.This method is to download and parse the star observation data of face battle array instrument；The star observation image sequence parsed is pre-processed；By the image sequences fusion after removing fixed pattern noise it is fixed star trace image using the method for image sequences fusion, and determines the fixed star track regions of the fixed star trace image；The fixed star number in image planes carries out fixed star identification with fixed fixed star track regions according to weather report, determines forecast fixed star corresponding fixed star region on every two field picture；Fixed star track fitting equation is obtained by fixed star track fitting method, and calculates accurate fixed star barycenter subpixel coordinates sequence；Most accurate fixed star barycenter subpixel coordinates are chosen from accurate fixed star barycenter subpixel coordinates sequence.Compared to the center-of-mass coordinate of single-frame images extraction, the fixed star barycenter subpixel coordinates determined using the method for the present invention are subject to influence of noise smaller, computational accuracy higher.
Description
Technical field
The present invention relates to a kind of fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument, belong to
Satellite image processing technology field.
Background technology
Stationary orbit earth observation satellite is located at about 35800 kilometers of terrestrial equator overhead, is run simultaneously with earth rotation, phase
To geostationary, the fixed area of earth surface 1/3rd can be observed, same objective area can be carried out constant
Observation, be the artificial earth satellite being observed from outer space to the earth and its atmosphere.
Stationary orbit earth observation satellite can improve earth observation precision, the observation frequency and sight using three-axle steady platform
The flexibility in region is surveyed, realizes technical great leap.But the gesture stability mode of three-axis stabilization, to stationary orbit pair
The high accuracy positioning of ground observation satellite brings very big challenge.And the high accuracy positioning of stationary orbit earth observation satellite depends on
In-orbit star observation.Therefore, high-precision fixed star barycenter extraction is the most important thing of stationary orbit earth observation satellite positioning,
Its precision directly affects the precision of satellite positioning, so as to affect the quantitative Application of product generation and data.
As shown in Figure 1, existing fixed star barycenter extracting method is based primarily upon single-frame images, due to being obtained after denoising
Single-frame images also include very strong fixed pattern noise, so as to have impact on opening for the detection to fixed star, identification and location algorithm
Exhibition；And it also is difficult to obtain high-precision fixed star center-of-mass coordinate using grey scale centre of gravity method based on single-frame images.
The content of the invention
The technical problems to be solved by the invention are to provide a kind of for stationary orbit earth observation satellite face battle array instrument
Fixed star barycenter extracting method.
To achieve these goals, the present invention uses following technical proposals：
A kind of fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument, includes the following steps：
Step S1：Download and parse the star observation data of stationary orbit earth observation satellite face battle array instrument；
Step S2：The star observation image sequence parsed is pre-processed；
Step S3：Using image sequences fusion method by remove fixed pattern noise after image sequences fusion be fixed star
Trace image, and determine the fixed star track regions of the fixed star trace image；
Step S4：The fixed star number in image planes carries out fixed star identification with fixed fixed star track regions according to weather report, really
Make forecast fixed star corresponding fixed star region on every two field picture；
Step S5：Fixed star track fitting equation is obtained by fixed star track fitting method, and it is sub- to calculate accurate fixed star barycenter
Pixel coordinate sequence；
Step S6：Most accurate fixed star barycenter subpixel coordinates are chosen from accurate fixed star barycenter subpixel coordinates sequence
As fixed star barycenter subpixel coordinates.
Wherein more preferably, in step S2, pretreatment is carried out to the star observation image sequence includes optics correction
With removal fixed pattern noise；
Wherein, during the optics correction, according to the echo cancellation table generated by cold empty and black matrix data,
Radiant correction is carried out to the gray value of each two field picture.
Wherein more preferably, during the fixed pattern noise is removed, reject in the star observation image sequence
Abnormal frame, asks for the average value of the gray value of the image sequence after rejecting abnormalities frame, as fixed pattern noise image；Wherein institute
The average gray for stating the same pixel of image sequence is expressed as：
Im(i, j) is the average gray of the same pixel of image sequence；Ik(i, j) be kth frame image in positioned at i-th row,
The gray value of the pixel of jth row；N is the totalframes of image sequence.
Wherein more preferably, in step S22, the gray value of original image described in every frame is subtracted into the fixed pattern noise figure
The gray value of picture, and after the gray value for subtracting each other pixel of the rear gray value less than 0 is set to 0, obtains and removes the fixed mode and make an uproar
Image sequence after sound.
Wherein more preferably, in step S3, described image sequence fusion method the step of it is as follows：
Step S31：Adaptive threshold method is selected to handle every two field picture into row threshold division；
Step S32：By the image sequences fusion after Threshold segmentation is handled into fixed star trace image；
Step S33：According to fixed star trace image, fixed star track regions are determined.
Wherein more preferably, in step S31, the segmentation threshold of every two field picture in the adaptive threshold method represents
For：
Tk=mean (Ik(i,j))+k'*std(Ik(i,j))
Wherein, TkFor the segmentation threshold of kth frame image, mean (Ik(i, j)) put down for the gray scale of the same pixel of image sequence
Average；Ik(i, j) is that k ' is constant coefficient positioned at the i-th row, the gray value of the pixel of jth row in kth frame image；std(Ik(i,j))
For the gray standard deviation of the same pixel of image sequence.
Wherein more preferably, in step S32, the gray value summation of the same pixel of multiple images sequence is tried to achieve, by described image
The same pixel gray value summation of sequence is fused into the fixed star trace image；The same pixel gray value summation table of described image sequence
It is shown as：
Wherein, Id(i, j) is the gray value summation of the same pixel of image sequence；Ik(i, j) is to be located at i-th in kth frame image
Arrange, the gray value of the pixel of jth row, N is image sequence totalframes.
Wherein more preferably, in step S33, the length detected on the fixed star trace image is expressed as：
ls=Vx·ts
Wherein, VxThe speed moved for fixed star in image planes, tsFor star observation duration.
Wherein more preferably, in step S4, when the fixed star number in forecast image planes is not less than 3, and the fixed star detected
When number is not less than 3, fixed star identification is carried out using triangle map algorithm；
When forecast image planes in the fixed star number be not less than 2, and the fixed star number detected be equal to 2；It is or pre-
Report image planes in the fixed star number be equal to 2, and the fixed star number detected be not less than 2 when, use angular distance characteristic matching
Algorithm carries out fixed star identification.
Wherein more preferably, during the triangle map algorithm carries out fixed star identification, calculate with being detected by any 3
The corresponding angular distance value of at least one observation triangle of the fixed star composition arrived, the angular distance value deviation, which is respectively less than, matches threshold
During value, it was demonstrated that the observation triangle corresponding with the angular distance value and at least one observation being made of the forecast fixed star
A successful match in triangle；The matching threshold isUnit pixel radian.
Wherein more preferably, when the right ascension declination of each fixed star detected of acquisition, fixed star described in two of which
Between angular distance be expressed as：
θd=arccos (cos βAcosβBcos(αA-αB)+sinβAsinβB)
θdFor the angular distance between two fixed stars, (αA,βA) be one of fixed star right ascension declination, (αB,βB) it is another
The right ascension declination of fixed star；
When the image coordinates of each fixed star detected of acquisition, the angular distance between two fixed stars represents
For：
θdFor the angular distance between two fixed stars, (xA,yA) be one of fixed star image coordinates, (xB,yB) it is another
The image coordinates of fixed star.
Wherein more preferably, during the angular distance Feature Correspondence Algorithm carries out fixed star identification, detected with any two
The fixed star be one group, using any two it is described forecast fixed stars as one group, using camera as vertex, calculate every group respectively and detect
The fixed star between and every group of forecast fixed star between angle, according to the angle determines at least one set of detect
Fixed star is matched with corresponding a certain group of forecast fixed star.
Wherein more preferably, in step S5, the step of fixed star track fitting method, is as follows：
Step S51：According to multiple fixed star regions of obtained star observation image sequence, the fixed star barycenter just extracted
Subpixel coordinates sequence；
Step S52：The mode being fitted using least-squares iteration rejects the fixed star barycenter subpixel coordinates sequence just extracted
Error dot；
Step S53：The fixed star barycenter subpixel coordinates sequence of first extraction after rejecting error dot is subjected to least square plan
Close, obtain fixed star track fitting equation, and calculate accurate fixed star barycenter subpixel coordinates sequence.
Wherein more preferably, in step S51, according to the definite corresponding fixed star region of every frame described image, the perseverance is obtained
Multiple fixed star regions are carried out just extraction by multiple fixed star regions of star observed image sequence using grey scale centre of gravity method respectively
Fixed star barycenter subpixel coordinates sequence calculates, and the fixed star barycenter subpixel coordinates sequence calculation formula of the just extraction is as follows：
Wherein, Ω is represented per the corresponding fixed star region of two field picture；I (i, j) is the energy of the pixel positioned at the i-th row, jth row
Response.
Wherein more preferably, in step S52, will be described at the beginning of the fixed star barycenter subpixel coordinates sequence extracted respectively with it is described into
As moment progress least square fitting, corresponding least square formula are as follows：
Wherein,Least square fitting parameter for the fixed star barycenter sub-pix abscissa just extracted；For
The fixed star barycenter sub-pix ordinate least square fitting parameter just extracted；tkFor the corresponding imaging moment of kth frame image；xkFor
The fixed star barycenter sub-pix abscissa just extracted in kth frame image；ykFor the fixed star barycenter sub-pix just extracted in kth frame image
Ordinate；N is image sequence totalframes.
Wherein more preferably, in step S53, the fixed star track fitting equation is expressed as：
Wherein, xaccu、yaccuFor the corresponding accurate fixed star barycenter subpixel coordinates of each two field picture tried to achieve；taccuTo be every
The corresponding imaging moment of one two field picture；Least square fitting ginseng for the fixed star barycenter sub-pix abscissa just extracted
Number；For the fixed star barycenter sub-pix ordinate least square fitting parameter just extracted.
Wherein more preferably, in step S6, chosen from the accurate fixed star barycenter subpixel coordinates sequence most accurate
The step of fixed star barycenter subpixel coordinates, is as follows：
Step S61：In fixed star barycenter subpixel coordinates sequence, calculate respectively each fixed star barycenter subpixel coordinates with it is right
Euclidean distance between the fixed star barycenter subpixel coordinates for the first extraction answered；
Step S62：The accurate perseverance of Euclidean distance minimum between selection and the fixed star barycenter subpixel coordinates just extracted
Star subpixel coordinates, as most accurate fixed star barycenter subpixel coordinates.
Fixed star barycenter extracting method one side provided by the present invention for stationary orbit earth observation satellite face battle array instrument
Face carries out optics correction using opposite battle array Instrument observation image sequence, removes fixed pattern noise processing respectively, not only carries
The high signal-to-noise ratio of image, also improves the accuracy rate of star observation.On the other hand, just extraction is obtained using grey scale centre of gravity method
The subpixel coordinates sequence of fixed star barycenter, and the error dot in the just fixed star barycenter subpixel coordinates sequence of extraction is rejected, use
Fixed star track fitting method suppresses influence of the error dot to fixed star track fitting equation, and the fixed star for making to finally obtain is fitted equation of locus
It is more accurate；Compared to single-frame images extraction center-of-mass coordinate, the fixed star center-of-mass coordinate that method using the present invention is determined by
To influence of noise smaller, computational accuracy higher.
Brief description of the drawings
Fig. 1 is the flow chart of existing fixed star barycenter extracting method；
Fig. 2 is the fixed star barycenter extracting method provided by the present invention for stationary orbit earth observation satellite face battle array instrument
Flow chart；
Fig. 3 A are the schematic diagram of single frames original image in fixed star barycenter extracting method provided by the present invention；
Fig. 3 B are in fixed star barycenter extracting method provided by the present invention, and single frames removes the signal of fixed pattern noise image
Figure；
Fig. 4 is in fixed star barycenter extracting method provided by the present invention, and stent is determined from original observed image sequence
Formula noise image；
Fig. 5 A are in fixed star barycenter extracting method provided by the present invention, are shown per two field picture into the effect before row threshold division
It is intended to；
Fig. 5 B are in fixed star barycenter extracting method provided by the present invention, are shown per two field picture into the effect after row threshold division
It is intended to；
Fig. 6 be fixed star barycenter extracting method provided by the present invention in, by the image sequences fusion after Threshold segmentation into
The method schematic diagram of fixed star trace image；
Fig. 7 is the schematic diagram of fixed star trace image in fixed star barycenter extracting method provided by the present invention；
Fig. 8 is in fixed star barycenter extracting method provided by the present invention, and fixed star track is determined on fixed star trace image
The schematic diagram in region；
Fig. 9 is in fixed star barycenter extracting method provided by the present invention, and fixed star identification is carried out to three fixed stars detected
Schematic diagram；
Figure 10 a are wherein three fixed star groups in the image planes of forecast in fixed star barycenter extracting method provided by the present invention
Into triangle schematic diagram；
Figure 10 b are in fixed star barycenter extracting method provided by the present invention, with wherein three fixed stars in the image planes of forecast
The corresponding navigational star table of triangle of composition；
Figure 10 c are in fixed star barycenter extracting method provided by the present invention, and fixed star knowledge is carried out according to triangle map algorithm
Other schematic diagram；
Figure 11 is in fixed star barycenter extracting method provided by the present invention, removes the abscissa sequence that fixed star barycenter just extracts
Error dot schematic diagram；
Figure 12 is in fixed star barycenter extracting method provided by the present invention, removes the ordinate sequence that fixed star barycenter just extracts
Error dot schematic diagram.
Embodiment
The technology contents of the present invention are described in further detail with specific embodiment below in conjunction with the accompanying drawings.
As shown in Fig. 2, provided by the present invention be used for stationary orbit earth observation satellite face battle array instrument (hereinafter referred to as face battle array
Instrument) fixed star barycenter extracting method include the following steps：
Step S1：Download and parse the star observation data of stationary orbit earth observation satellite face battle array instrument；
The star observation data from the face that stationary orbit earth observation satellite passes down battle array instrument are downloaded, due to the perseverance of download
Star observation data exist in the form of data APMB package, therefore according to format description, can be from the star observation data packet of download
The information such as star observation image sequence, image imaging moment, imaging frame frequency are parsed in file, to be follow-up high-precision perseverance
The extraction of star barycenter lays the foundation.Wherein, in star observation image sequence, each frame star observation picture size is 330 × 256 pictures
Element.
Step S2：The star observation image sequence parsed is pre-processed；
The star observation image sequence parsed needs to carry out optics correction successively, at fixed pattern noise removal
Reason；Wherein, when carrying out optics correction to star observation image sequence, since the different pixels of instrument are to the sensitiveness of light
There is some difference, therefore can use the echo cancellation table by scaling system using data acquisitions such as cold empty and black matrixes, and
Radiant correction is carried out to the gray value of each two field picture according to echo cancellation table, i.e., the mapping in echo cancellation table is closed
System corrects each pixel gray value in each two field picture (each two field picture includes 84480 pixels).To each two field picture
The purpose that gray value carries out radiant correction is：1st, eliminate as much as because of the atmospheric conditions such as sensor self-condition, mist, the sun
Position and angle conditions and some inevitably measured value of sensor and the spectral reflectivities of target caused by noise etc. or
Difference between the physical quantitys such as spectral radiance；2nd, recover the true colours of image as far as possible, be the identification of remote sensing images, divide
The follow-up works such as class, interpretation lay the foundation.
Due to the influence of the external stray lights such as earth atmosphere reflected light, can be included in the star observation image sequence parsed
Very strong fixed pattern noise (as shown in Figure 3A), has seriously affected signal noise ratio (snr) of image；Therefore, star observation image sequence is removed
In fixed pattern noise can effectively lift signal noise ratio (snr) of image (as shown in Figure 3B), it is ensured that the inspection of follow-up fixed star barycenter
Survey, identify, the development of location algorithm.When star observation image sequence being fixed modal noise removal processing, can adopt
Use following steps：
Step S21：Calculate fixed pattern noise image；
As shown in figure 4, rejecting the abnormal frame in original star observation image sequence, the image sequence after rejecting abnormalities frame is asked for
The average value of the gray value of row, as fixed pattern noise image.Wherein, the average gray table of the same pixel of image sequence
It is shown as：
Wherein, Im(i, j) be image sequence same pixel average gray, Ik(i, j) is to be located in kth frame image
I-th arranges, the gray value of the pixel of jth row, and N is the totalframes of image sequence.Since a two field picture is made of 84480 pixels,
Therefore 84480 average gray can be tried to achieve by formula (1), this 84480 average gray constitute fixed pattern noise figure
Picture.
Step S22：According to fixed pattern noise image, determine to remove the image sequence after fixed pattern noise；
The gray value of every frame original image is subtracted to the gray value of fixed pattern noise image, and it is small to subtract each other rear gray value
0 is set in the gray value of 0 pixel, you can obtains the image sequence after removing fixed pattern noise.
Step S3：Using image sequences fusion method by remove fixed pattern noise after image sequences fusion be fixed star
Trace image, and determine the fixed star track regions of the fixed star trace image；
In the image sequence after removing fixed pattern noise, stars are in acnode shape on every two field picture, due to phase
The presence in gap between adjacent two row pixels, the pixel around fixed star barycenter in 3 × 3 pixel regions might have energy response, but
Target is overall smaller, and feature is weaker, and close with noise feature；When fixed star is dark, almost cannot be distinguished by with noise.If directly
The detection of fixed star signal response region is carried out on single-frame images, obtained false-alarm is more, can seriously affect high-precision fixed star barycenter
The development of extraction algorithm.Therefore, the method that the present invention uses image sequences fusion, is one by the image sequences fusion containing any stars
Width includes the image of any stars track, then carries out star observation on the width image, determines fixed star track regions.The image
The method of sequence fusion includes the following steps：
Step S31：Adaptive threshold method is selected to handle every two field picture into row threshold division；
The signal noise ratio (snr) of image of image sequence after fixed pattern noise removes is significantly improved, but in image sequence also
There is the gray value of more pixel non-zero, cause to influence to determine the fixed star region of fixed star trace image.Therefore, select adaptive
For threshold method to every two field picture into row threshold division processing, the segmentation threshold calculation formula per two field picture is as follows：
Tk=mean (Ik(i,j))+k'*std(Ik(i,j)) (2)
Wherein, TkFor the segmentation threshold of kth frame image, mean (Ik(i, j)) put down for the gray scale of the same pixel of image sequence
Average；Ik(i, j) is positioned at the i-th row, the gray value of the pixel of jth row in kth frame image, and k ' is constant coefficient (standard deviation times
Number)；std(Ik(i, j)) for image sequence same pixel gray standard deviation.In every two field picture, each pixel is subtracted
The corresponding segmentation threshold of the two field picture, and by the minus pixel zero setting of result, obtain further removing the image after noise.
Shown in Fig. 5 A and Fig. 5 B, through experiment test, when k ' takes 3, the result handled per two field picture into row threshold division is preferable.
Step S32：By the image sequences fusion after Threshold segmentation is handled into fixed star trace image；
As shown in Figure 6 and Figure 7, since in the image sequence after the processing of step S31 Threshold segmentations, each two field picture has
One asterism, then the asterism of image sequence is combined, the image that a width includes any stars track can be fused into.By
It is made of in a two field picture 84480 pixels, therefore the gray value that can try to achieve by formula below (3) the same pixel of image sequence is total
With obtain 84480 gray value summations altogether, this 84480 gray value summations have been fused into fixed star trace image (such as Fig. 7 institutes
Show).The gray value summation of the same pixel of image sequence is expressed as：
Wherein, Id(i, j) is the gray value summation of the same pixel of image sequence；Ik(i, j) is to be located at i-th in kth frame image
Arrange, the gray value of the pixel of jth row, N is image sequence totalframes.
Step S33：According to fixed star trace image, fixed star track regions are determined
Due to that may have the movement locus of more fixed stars in the fixed star trace image that step S32 is determined, therefore, it is necessary to
The number of fixed star is confirmed on identified fixed star trace image, so as to obtain fixed star track regions.In stationary orbit over the ground
In observation satellite, fixed star streaks straight line track, and rectilinear direction level of approximation in face battle array instrument image planes.Fixed star is in image planes
The speed calculation formula of movement is as follows：
Wherein, T is satellite orbit period, and the orbital period of stationary orbit earth observation satellite is equal to a sidereal day, i.e.,
23h56min4s；R is face battle array instrument angular resolution, i.e., the corresponding optics subtended angle of each pixel, is 56 μ rad/px.Through formula
(4) can be calculated, fixed star movement velocity in the battle array instrument image planes of face is equal to 1.2986px/s.Therefore, fixed star path length can be with
It is expressed as：
ls=Vx·ts (5)
Wherein, VxThe speed moved for fixed star in image planes, tsFor star observation duration.Star observation duration is about 8s, permanent
Star trails length is 10.389px/s.In view of the influence of noise, the line segment of detection length >=8px on fixed star trace image,
The higher fixed star track regions of confidence level can be obtained.For example, as shown in figure 8, in the fixed star trace image that step S32 is determined
Detect the line segment of three length >=8px, you can determine there is the movement locus of three fixed stars in the fixed star trace image, from
And define fixed star track regions.
Step S4：The fixed star number in image planes carries out fixed star identification with fixed fixed star track regions according to weather report, really
Make forecast fixed star corresponding fixed star region on every two field picture；
Fixed star forecast system (external system) can provide the ephemeris information for the fixed star being likely to occur in the battle array instrument image planes of face, as
Fixed star basis of characterization；Fixed star number in image planes and fixed fixed star track regions (the fixed star number detected according to weather report
Mesh), following several situations can be divided into：
(1) when fixed star number >=3 in forecast image planes, during and the fixed star number detected >=3, calculated using triangle map
Method carries out fixed star identification.During triangle map algorithm carries out fixed star identification, as shown in 9 figures, if in forecast image planes
Fixed star number is 3, and the fixed star number detected is also 3 (including fixed star A, fixed star B and fixed star C), with angular distance characteristic matching principle
Identical, the three fixed star asterism targets detected may be constructed an observation triangle.Calculate three perseverances under celestial coordinate system
Angular distance between star, wherein, angular distance is expressed as between two fixed stars：
θd=arccos (cos βAcosβBcos(αA-αB)+sinβAsinβB) (6)
As as-shown-in figures 10 a and 10b, three fixed stars of forecast can build a navigational star table, and wherein α represents fixed star warp
Degree, δ represent fixed star latitude, and m represents stellar magnitude, and d is the angular distance between two fixed stars, need to be by three perseverances to eliminate singularity
Star inserts navigational star table with certain rule.But found by experimental analysis, sorted using magnitude, asterism monochrome information reliability
Low, asterism positional information is more reliable in contrast.Therefore, when building navigational star table, carried out according to fixed star right ascension (X-coordinate)
Sequence, ensures α in each navigational star table1＜ α2＜ α3.In field range (as shown in figure l0c), three fixed stars of forecast can be with
Form an observation triangle.
If assuming, fixed star A right ascensions declination is (αA,βA), fixed star B right ascensions declination is (αB,βB), bring formula (6) into and draw two
Angular distance is arccos (cos β between fixed star (fixed star A and fixed star B)AcosβBcos(αA-αB)+sinβAsinβB).Assuming that fixed star A pictures
Areal coordinate is (xA,yA), the image coordinates of fixed star B is (xB,yB), unit pixel radian is θ, then two stars (fixed star A and fixed star B)
Between angular distance be：
Calculated respectively in the triangle being made of three fixed stars detected using formula (6) or formula (7), fixed star
Angular distance between A and fixed star C and between fixed star B and fixed star C.As shown in figure l0c, the observation detect three fixed stars formed
The observation triangle that triangle is formed with by navigational star table is matched, if corresponding three groups of angular distance value deviations are respectively less than matching threshold
δT, then it is assumed that two triangle successful match.The fixed star center-of-mass coordinate extracted by gray scale center method is fully taken into account in X, Y-direction
There are certain deviation, it is assumed that fixed star center-of-mass coordinate is respectively less than 0.5 pixel in X, Y-direction deviation, takes the angular distance matching threshold to be
Unit pixel radian.I.e. matching threshold can be expressed as：
Since in the face battle array of face battle array instrument, each 56 μ rad of pixel subtended angle, then matching threshold is 79.2 μ rad.
During triangle map algorithm carries out fixed star identification, if the fixed star number in forecast image planes is more than 3, detection
The fixed star number arrived is more than 3, can form an observation triangle by any three fixed stars of selection as original in the fixed star of forecast
Then, multiple observation triangles are combined into.In the fixed star detected three fixed stars compositions, one observation triangle is chosen by any
For principle, multiple observation triangles are also combined into, and each observation triangle is calculated respectively using formula (6) or formula (7)
Corresponding three groups of angular distances.By the multiple observation triangles being made of the fixed star detected and the multiple observations being made of forecast fixed star
Triangle is matched, if corresponding three groups of angular distance value deviations are respectively less than matching threshold δT, then it is assumed that it is made of the fixed star detected
Multiple observation triangles in, observation triangle corresponding with three groups of angular distance values and multiple observation triangles for being made of forecast fixed star
A successful match in shape.
(2) when fixed star number >=2 in forecast image planes, and fixed star number=2 detected；Or the perseverance in forecast image planes
Star number mesh=2, during and the fixed star number detected >=2, use angular distance Feature Correspondence Algorithm to carry out fixed star identification.In angular distance feature
During matching algorithm carries out fixed star identification, angular distance refers to the angular distance between two celestial bodies.For example, 1. when in forecast image planes
Fixed star number be 2, the fixed star number detected also be 2 when, by two that calculate detect two fixed stars and forecast
The angle that fixed star is made of with camera vertex respectively, if two fixed stars detected and the angle that camera is formed and forecast
Two angles formed between fixed star and camera are equal, and two fixed stars for illustrating to detect are forecast fixed star, can be made respectively
For the object of final extraction fixed star barycenter.2. when forecasting that the fixed star number in image planes is 3, when the fixed star number detected is 2, lead to
The angle that two fixed stars for calculating and detecting are made of with camera vertex is crossed, due to any two in 3 fixed stars of forecast
Fixed star has combined 3 kinds of situations, the angle between the forecast fixed star of this 3 kinds of situations and camera is calculated respectively, if detecting
2 fixed stars combined with the angle and any of which that camera is formed forecast fixed star and camera between angle it is equal,
2 fixed stars for illustrating to detect are forecast fixed star, can be respectively as the object of final extraction fixed star barycenter.3. when forecast image planes
Interior fixed star number is 2, when the fixed star number detected is 3, by calculating two fixed stars of forecast using camera as vertex institute
The angle of composition, since any two fixed stars have combined 3 kinds of situations in 3 fixed stars detecting, calculates this 3 kinds respectively
Angle between the fixed star and camera of situation, if detecting angle and forecast that fixed star and the camera of any one combination formed
Angle between fixed star and camera is equal, and 2 fixed stars of this kind combination for illustrating to detect are forecast fixed star, can be respectively as
The object of final extraction fixed star barycenter.
(3) when fixed star number=1 in forecast image planes, during and the fixed star number detected=1, without carrying out fixed star knowledge
Not, it is believed that the fixed star detected is to forecast fixed star, which is the final object for extracting fixed star barycenter.
(4) forecast fixed star number >=2 in image planes, during and the fixed star number detected=1, fixed star identification can not be carried out,
Tasks carrying failure is judged, so as to abandon the fixed star barycenter extraction to this image sequence.
Fixed star is forecast according to determined by this step, it may be determined that go out corresponding fixed star region on every two field picture.For example, this
Step defines 1 forecast fixed star, then per corresponding fixed star region on two field picture for 3 around the forecast fixed star barycenter ×
3 pixel regions.
Step S5：Fixed star track fitting equation is obtained by fixed star track fitting method, and it is sub- to calculate accurate fixed star barycenter
Pixel coordinate sequence；
The fixed star track fitting equation obtained by fixed star track fitting method, can be subsequently from face battle array instrument star observation
Accurately extraction fixed star center-of-mass coordinate sequence lays the foundation in image sequence.The fixed star track fitting method comprises the following steps that：
Step S51：According to multiple fixed star regions of obtained star observation image sequence, the fixed star barycenter just extracted
Subpixel coordinates sequence；
The corresponding fixed star region of every two field picture (3 × 3 pixel scope) determined according to step S4, has obtained star observation figure
As multiple fixed star regions of sequence, carrying out preliminary extraction fixed star barycenter subpixel coordinates using grey scale centre of gravity method respectively, (X, Y are sat
Mark) sequence calculating.Calculation formula is as follows：
Wherein, Ω is represented per the corresponding fixed star region of frame described image, and I (i, j) is the pixel positioned at the i-th row, jth row
Gray value.In present treatment algorithm, 3 × 3 pixel scopes are taken.According to formula (9), multiple just fixed star barycenter of extraction can be calculated
Coordinate sequence { (x1,y1),(x2,y2)...(xN,yN), N represents fixed star number of regions corresponding with star observation image sequence, N
For positive integer；xNFor the fixed star barycenter sub-pix abscissa of the corresponding just extraction in n-th fixed star region；yNFor n-th fixed star region
The fixed star barycenter sub-pix ordinate of corresponding just extraction.It is emphasized that if forecast fixed star is more determined by step 4
, then 3 × 3 pixel regions in more forecast fixed stars on per two field picture fixed star region around every forecast fixed star barycenter,
When calculating the just fixed star barycenter subpixel coordinates sequence of extraction, it is necessary to calculate the fixed star of the first extraction of every forecast fixed star respectively
Barycenter subpixel coordinates sequence.
Step S52：The mode being fitted using least-squares iteration rejects the fixed star barycenter subpixel coordinates sequence just extracted
Error dot；
Since noise, algorithm power limitations etc. influence, the fixed star barycenter subpixel coordinates just extracted are sub- with fixed star barycenter
Between pixel coordinate true value often accurate fixed star barycenter subpixel coordinates extraction mission requirements is unsatisfactory for there are certain deviation.And
And there are larger deviation, meeting between the fixed star barycenter subpixel coordinates and fixed star barycenter subpixel coordinates true value of indivedual first extractions
Large effect is produced to fixed star track fitting equation, reduces the precision of fixed star track fitting.Therefore, it is necessary to use a most young waiter in a wineshop or an inn
The mode for multiplying iterative fitting rejects error dot in the fixed star barycenter subpixel coordinates sequence just extracted.
Since subpixel coordinates sequence of the fixed star barycenter in the first extraction in transverse direction (X-direction), longitudinal direction (Y-direction) direction is deposited
In error, and imaging moment is accurate in contrast, thus by the fixed star barycenter subpixel coordinates sequence just extracted respectively with
Imaging moment carries out least square fitting.The corresponding least square formula of fixed star barycenter subpixel coordinates sequence just extracted is such as
Under：
Wherein,Least square fitting parameter for the fixed star barycenter sub-pix abscissa just extracted；For
The fixed star barycenter sub-pix ordinate least square fitting parameter just extracted, tkFor the corresponding imaging moment of kth frame image, xkKth
The fixed star barycenter sub-pix abscissa just extracted in two field picture, ykFor just the fixed star barycenter sub-pix of extraction is indulged in kth frame image
Coordinate, N are image sequence totalframes.It will deviate from the fixed star barycenter transverse direction and longitudinal direction of the first extraction of fitting a straight line distance 20% respectively
Direction subpixel coordinates are considered as worst error point, and are rejected, to ensure fully to reject error dot, the fixed star matter that will just extract
Heart subpixel coordinates sequence carries out 3 least square fittings with imaging moment respectively.As shown in figure 11, will deviate from fitting a straight line away from
The fixed star barycenter horizontal direction sub-pix ordinate of first extraction from 20% is considered as worst error point, and is rejected；Such as Figure 12
Shown, the sub-pix ordinate that will deviate from the fixed star barycenter longitudinal direction just extraction of fitting a straight line distance 20% is considered as worst error
Point, and rejected；Least square fitting three times so is repeated to the fixed star barycenter subpixel coordinates just extracted, ensures to fill
Divide the error dot rejected in the just fixed star barycenter subpixel coordinates of extraction.
Step S53：The fixed star barycenter subpixel coordinates sequence of first extraction after rejecting error dot is subjected to least square plan
Close, obtain fixed star track fitting equation, and calculate accurate fixed star barycenter subpixel coordinates sequence.
The fixed star barycenter subpixel coordinates sequence for rejecting the first extraction after error dot carries out least square fitting, obtains fixed star
Track fitting equation is as follows：
Wherein, xaccu、yaccuRepresent the corresponding accurate fixed star barycenter subpixel coordinates of each two field picture tried to achieve, taccuTable
Show the corresponding imaging moment of each two field picture (image sequence observes the moment)； Represent the horizontal seat of the just fixed star barycenter of extraction
Target least square fitting parameter；Represent the ordinate least square fitting parameter of the just fixed star barycenter of extraction.Utilize
Formula (14) can try to achieve accurate fixed star barycenter subpixel coordinates sequence.
Step S6：Most accurate fixed star barycenter subpixel coordinates are chosen from accurate fixed star barycenter subpixel coordinates sequence
As fixed star barycenter subpixel coordinates.
The step of most accurate fixed star barycenter subpixel coordinates being chosen from accurate fixed star barycenter subpixel coordinates sequence
It is as follows：
Step S61：In accurate fixed star barycenter subpixel coordinates sequence, each accurate fixed star sub-pix is calculated respectively
Euclidean distance between coordinate and the corresponding just fixed star barycenter subpixel coordinates of extraction；
The each accurate fixed star subpixel coordinates calculated respectively are sat with the fixed star barycenter sub-pix of corresponding just extraction
Euclidean distance between mark, as the foundation for choosing most accurate fixed star center-of-mass coordinate；
Step S62：The accurate perseverance of Euclidean distance minimum between selection and the fixed star barycenter subpixel coordinates just extracted
Star subpixel coordinates, as most accurate fixed star barycenter subpixel coordinates.
Fixed star barycenter extracting method one side provided by the present invention for stationary orbit earth observation satellite face battle array instrument
Face carries out optics correction using opposite battle array Instrument observation image sequence, removes fixed pattern noise processing respectively, not only carries
The high signal-to-noise ratio of image, also improves the accuracy rate of star observation.On the other hand, just extraction is obtained using grey scale centre of gravity method
The subpixel coordinates sequence of fixed star barycenter, and the error dot in the just fixed star barycenter subpixel coordinates sequence of extraction is rejected, use
Fixed star track fitting method suppresses influence of the error dot to fixed star track fitting equation, and the fixed star for making to finally obtain is fitted equation of locus
It is more accurate；Compared to single-frame images extraction center-of-mass coordinate, the fixed star center-of-mass coordinate that method using the present invention is determined by
To influence of noise smaller, computational accuracy higher.
Above to the fixed star barycenter extraction side provided by the present invention for stationary orbit earth observation satellite face battle array instrument
Method is described in detail.For those of ordinary skill in the art, on the premise of without departing substantially from true spirit
Any obvious protection domain changed, will all belong to patent right of the present invention done to it.
Claims (17)
1. a kind of fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument, it is characterised in that including such as
Lower step：
Step S1：Download and parse the star observation data of stationary orbit earth observation satellite face battle array instrument；
Step S2：The star observation image sequence parsed is pre-processed；
Step S3：Using image sequences fusion method by remove fixed pattern noise after image sequences fusion be fixed star track
Image, and determine the fixed star track regions of the fixed star trace image；
Step S4：The fixed star number in image planes carries out fixed star identification with fixed fixed star track regions according to weather report, determines
Forecast fixed star corresponding fixed star region on every two field picture；
Step S5：Fixed star track fitting equation is obtained by fixed star track fitting method, and calculates accurate fixed star barycenter sub-pix
Coordinate sequence；
Step S6：Most accurate fixed star barycenter subpixel coordinates conduct is chosen from accurate fixed star barycenter subpixel coordinates sequence
Fixed star barycenter subpixel coordinates.
2. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 1, its
It is characterized in that：
In step S2, to the star observation image sequence carry out pretreatment include optics correction and removal fixed mode make an uproar
Sound；Wherein, during the optics correction, according to the echo cancellation table generated by cold empty and black matrix data, and root
Radiant correction is carried out to the gray value of each two field picture according to the echo cancellation table.
3. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 2, its
It is characterized in that：
During the fixed pattern noise is removed, the abnormal frame in the star observation image sequence is rejected, asks for rejecting
The average value of the gray value of image sequence after abnormal frame, as fixed pattern noise image；Wherein described image sequence is same
The average gray of one pixel is expressed as：
<mrow>
<msub>
<mi>I</mi>
<mi>m</mi>
</msub>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mfrac>
<mrow>
<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>k</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<msub>
<mi>I</mi>
<mi>k</mi>
</msub>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
<mi>N</mi>
</mfrac>
</mrow>
Im(i, j) is the average gray of the same pixel of image sequence；Ik(i, j) is positioned at the i-th row, jth in kth frame image
The gray value of capable pixel；N is the totalframes of image sequence.
4. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 3, its
It is characterized in that：
In step S22, the gray value of original image described in every frame is subtracted to the gray value of the fixed pattern noise image, and will
Subtract each other pixel of the rear gray value less than 0 gray value be set to 0 after, obtain the image sequence after removing the fixed pattern noise.
5. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 1, its
Be characterized in that in step s3, described image sequence fusion method the step of it is as follows：
Step S31：Adaptive threshold method is selected to handle every two field picture into row threshold division；
Step S32：By the image sequences fusion after Threshold segmentation is handled into fixed star trace image；
Step S33：According to fixed star trace image, fixed star track regions are determined.
6. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 5, its
It is characterized in that in step S31, the segmentation threshold of every two field picture in the adaptive threshold method is expressed as：
Tk=mean (Ik(i, j))+k ' * std (Ik(i, j))
Wherein, TkFor the segmentation threshold of kth frame image, mean (Ik(i, j)) it is averaged for the gray scale of the same pixel of image sequence
Value；Ik(i, j) is that k ' is constant coefficient positioned at the i-th row, the gray value of the pixel of jth row in kth frame image；std(Ik(i, j)) be
The gray standard deviation of the same pixel of image sequence.
7. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 5, its
It is characterized in that：
In step S32, the gray value summation of the same pixel of multiple images sequence is tried to achieve, by the same pixel gray scale of described image sequence
Value summation is fused into the fixed star trace image；The same pixel gray value summation of described image sequence is expressed as：
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<mi>I</mi>
<mi>d</mi>
</msub>
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<mo>)</mo>
</mrow>
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<munderover>
<mo>&Sigma;</mo>
<mrow>
<mi>k</mi>
<mo>=</mo>
<mn>1</mn>
</mrow>
<mi>N</mi>
</munderover>
<msub>
<mi>I</mi>
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</msub>
<mrow>
<mo>(</mo>
<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
Wherein, Id(i, j) is the gray value summation of the same pixel of image sequence；Ik(i, j) be kth frame image in positioned at i-th row,
The gray value of the pixel of jth row, N are image sequence totalframes.
8. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 5, its
It is characterized in that：
In step S33, the length detected on the fixed star trace image is expressed as：
ls=Vx·ts
Wherein, VxThe speed moved for fixed star in image planes, tsFor star observation duration.
9. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 1, its
It is characterized in that：
In step S4, when the fixed star number in forecast image planes is not less than 3, and the fixed star number detected is not less than 3, make
Fixed star identification is carried out with triangle map algorithm；
When forecast image planes in the fixed star number be not less than 2, and the fixed star number detected be equal to 2；Or forecast picture
The fixed star number in face is equal to 2, and when the fixed star number detected is not less than 2, uses angular distance Feature Correspondence Algorithm
Carry out fixed star identification.
10. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 9, its
It is characterized in that：
During the triangle map algorithm carries out fixed star identification, calculate and by any 3 fixed star groups detected
Into the corresponding angular distance value of at least one observation triangle, when the angular distance value deviation is respectively less than matching threshold, it was demonstrated that with institute
State the corresponding observation triangle of angular distance value and by one at least one observation triangle for forecasting fixed star and forming
A successful match；The matching threshold isUnit pixel radian.
11. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 10,
It is characterized in that：
When the right ascension declination of each fixed star detected of acquisition, the angular distance between fixed star described in two of which represents
For：
θd=arccos (cos βAcosβBcos(αA-αB)+sinβAsinβB)
θdFor the angular distance between two fixed stars, (αA, βA) be one of fixed star right ascension declination, (αB, βB) it is another fixed star
Right ascension declination；
When the image coordinates of each fixed star detected of acquisition, the angular distance between two fixed stars is expressed as：
<mrow>
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<mi>&theta;</mi>
<mi>d</mi>
</msub>
<mo>=</mo>
<mi>&theta;</mi>
<msqrt>
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<mn>2</mn>
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</msub>
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<mi>y</mi>
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</msub>
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</mrow>
<mn>2</mn>
</msup>
</mrow>
</msqrt>
</mrow>
θdFor the angular distance between two fixed stars, (xA, yA) be one of fixed star image coordinates, (xB, yB) it is another fixed star
Image coordinates.
12. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 9, its
It is characterized in that：
During the angular distance Feature Correspondence Algorithm carries out fixed star identification, using any two fixed stars detected as one
Group, using any two forecast fixed stars as one group, using camera as vertex, calculates between every group of fixed star detected respectively
And the angle between every group of forecast fixed star, according to the angle determine at least one set of fixed star detected with it is corresponding certain
One group of forecast fixed star matching.
13. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 1, its
It is characterized in that：
In step S5, the step of fixed star track fitting method, is as follows：
Step S51：According to multiple fixed star regions of obtained star observation image sequence, the fixed star barycenter Asia picture just extracted
Plain coordinate sequence；
Step S52：The mode being fitted using least-squares iteration rejects the mistake for the fixed star barycenter subpixel coordinates sequence just extracted
Almost；
Step S53：The fixed star barycenter subpixel coordinates sequence of first extraction after rejecting error dot is subjected to least square fitting, is obtained
To fixed star track fitting equation, and calculate accurate fixed star barycenter subpixel coordinates sequence.
14. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 13,
It is characterized in that：
In step S51, according to the definite corresponding fixed star region of every frame described image, the star observation image sequence is obtained
Multiple fixed star regions, the fixed star barycenter sub-pix that respectively multiple fixed star regions are carried out with just extraction using grey scale centre of gravity method are sat
Mark sequence to calculate, the fixed star barycenter subpixel coordinates sequence calculation formula of the just extraction is as follows：
<mfenced open = "{" close = "">
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<mi>x</mi>
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<mo>&CenterDot;</mo>
<mi>j</mi>
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</mrow>
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<mo>&Sigma;</mo>
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<mo>(</mo>
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<mo>&Element;</mo>
<mi>&Omega;</mi>
</mrow>
</msub>
<mi>I</mi>
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<mi>i</mi>
<mo>,</mo>
<mi>j</mi>
<mo>)</mo>
</mrow>
</mrow>
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</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
Wherein, Ω is represented per the corresponding fixed star region of two field picture；I (i, j) is the energy response of the pixel positioned at the i-th row, jth row
Value.
15. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 14,
It is characterized in that：
In step S52, will be described at the beginning of the fixed star barycenter subpixel coordinates sequence extracted carried out respectively with the imaging moment it is minimum
Two multiply fitting, and corresponding least square formula is as follows：
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<mo>=</mo>
<mfrac>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msup>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mn>2</mn>
</msup>
<mo>)</mo>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
<mo>-</mo>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
<mrow>
<mi>N</mi>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msup>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<mo>-</mo>
<msup>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mover>
<mi>b</mi>
<mo>^</mo>
</mover>
<mi>y</mi>
</msub>
<mo>=</mo>
<mfrac>
<mrow>
<mi>N</mi>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>y</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
</mrow>
<mrow>
<mi>N</mi>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msup>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<mo>-</mo>
<msup>
<mrow>
<mo>(</mo>
<mo>&Sigma;</mo>
<msub>
<mi>t</mi>
<mi>k</mi>
</msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
</mrow>
</mfrac>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
<mrow>
<mover>
<mi>y</mi>
<mo>^</mo>
</mover>
<mo>=</mo>
<msub>
<mover>
<mi>a</mi>
<mo>^</mo>
</mover>
<mi>y</mi>
</msub>
<mo>+</mo>
<msub>
<mover>
<mi>b</mi>
<mo>^</mo>
</mover>
<mi>y</mi>
</msub>
<mi>t</mi>
</mrow>
Wherein,Least square fitting parameter for the fixed star barycenter sub-pix abscissa just extracted；Just to carry
The fixed star barycenter sub-pix ordinate least square fitting parameter taken；tkFor the corresponding imaging moment of kth frame image；xkFor kth frame
The fixed star barycenter sub-pix abscissa just extracted in image；ykFor just the fixed star barycenter sub-pix of extraction indulges seat in kth frame image
Mark；N is image sequence totalframes.
16. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 15,
It is characterized in that：
In step S53, the fixed star track fitting equation is expressed as：
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msub>
<mi>x</mi>
<mrow>
<mi>a</mi>
<mi>c</mi>
<mi>c</mi>
<mi>u</mi>
</mrow>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>a</mi>
<mo>^</mo>
</mover>
<mi>x</mi>
</msub>
<mo>+</mo>
<msub>
<mi>b</mi>
<mi>x</mi>
</msub>
<mo>&CenterDot;</mo>
<msub>
<mi>t</mi>
<mrow>
<mi>a</mi>
<mi>c</mi>
<mi>c</mi>
<mi>u</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<msub>
<mi>y</mi>
<mrow>
<mi>a</mi>
<mi>c</mi>
<mi>c</mi>
<mi>u</mi>
</mrow>
</msub>
<mo>=</mo>
<msub>
<mover>
<mi>a</mi>
<mo>^</mo>
</mover>
<mi>y</mi>
</msub>
<mo>+</mo>
<msub>
<mover>
<mi>b</mi>
<mo>^</mo>
</mover>
<mi>y</mi>
</msub>
<mo>&CenterDot;</mo>
<msub>
<mi>t</mi>
<mrow>
<mi>a</mi>
<mi>c</mi>
<mi>c</mi>
<mi>u</mi>
</mrow>
</msub>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
Wherein, xaccu、yaccuFor the corresponding accurate fixed star barycenter subpixel coordinates of each two field picture tried to achieve；taccuFor each frame
The corresponding imaging moment of image；Least square fitting parameter for the fixed star barycenter sub-pix abscissa just extracted；For the fixed star barycenter sub-pix ordinate least square fitting parameter just extracted.
17. the fixed star barycenter extracting method for stationary orbit earth observation satellite face battle array instrument as claimed in claim 1, its
It is characterized in that：
In step S6, the most accurate fixed star barycenter Asia picture is chosen from the accurate fixed star barycenter subpixel coordinates sequence
The step of plain coordinate, is as follows：
Step S61：In accurate fixed star barycenter subpixel coordinates sequence, calculate respectively each fixed star barycenter subpixel coordinates with
Euclidean distance between the corresponding just fixed star barycenter subpixel coordinates of extraction；
Step S62：The accurate fixed star of Euclidean distance minimum between selection and the fixed star barycenter subpixel coordinates just extracted is sub-
Pixel coordinate, as most accurate fixed star barycenter subpixel coordinates.
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