CN102853851B - The imaging system of computer simulation star sensor stellar field and formation method - Google Patents

Abstract

The present invention relates to a kind of imaging system of computer simulation star sensor stellar field, comprising: observation sing data storehouse; The user input set up in ZEMAX optical design software, its optical axis being suitable for the optical module set in ZEMAX optical design software points to, the pixel number of image planes detector and size; Be suitable for the expansion module that described ZEMAX optical design software is called, comprise: extract observation star module, calculate field positions module, calculate pixel gray scale module; ZEMAX optical design software, also comprises ray tracing module, and described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives; Can obtain the star chart data of mating with detector in the present invention, according to Pixel size and the number of user's input, described calculating pixel gray scale module, to image planes data sampling and quantification, calculates the brightness of each pixel, exports the digital star chart mated with detector.

Description

The imaging system of computer simulation star sensor stellar field and formation method

Technical field

The invention belongs to celestial navigation technology neighborhood, relate to a kind of computer simulation star sensor that uses to obtain imaging system and the formation method of digital star chart.

Background technology

Star sensor is one of attitude measurement instrument that current precision is the highest, has become the study hotspot in aerospace navigation field.In star sensor research process, need a large amount of star charts for verifying and assess feasibility and the performance of correlation technique, for program development, debugging, Performance Evaluation and model machine ground experiment.The present invention studies computer simulation stellar field formation method, proposes a kind of based on existing optical design system platform, carries out the method for computer simulation star sensor stellar field imaging, obtain digital star chart, and set up corresponding simulation system.

The external stellar field Imaging Simulation technology that begins one's study very early.At present, domestic have two analoglike methods, becomes two developing direction.

The first kind produces simulation star or analog starry sky by computing machine control, then obtain simulation star chart by star sensor imaging, and this kind of analogy method can be applied to ground experiment and the ground demarcation of star sensor.As nineteen ninety-five is published in " Spacecraft Environment Engineering " the 1st " real-time star map simulator scheme imagination " of phase, be published in a kind of " method of CCD Star Image Simulation " of " China's Space science and technology " the 19th volume the 3rd phase with 1999, the simulation star chart that institute's extracting method obtains is used for system debug and ground experiment.For another example " optical precision engineering " the 15th method of reporting of " the small-sized star simulator design based on digital light treatment technology " of volume o. 11th within 2007, is published in.The system architecture that this kind of analogy method relates to is complicated, and cost is high.

Equations of The Second Kind is directly simulated on computers and export digital star chart, and the star chart of acquisition is mainly used in the research of obtaining star location, importance in star map recognition, attitude estimation scheduling algorithm.As 2000, the star sensor star image system of ray machine place, Changchun " optical precision engineering " the 8th volume the 3rd phase report, this system has the function simulating basic imaging circumstances, gained numeral star chart is used for star Pattern Recognition Algorithm research, but fails the consideration actual imaging process of optical system and aberration to the impact of picture element.2009, in " 9thInternationalConferenceonDgitalObjectIdentifier " meeting, BJ University of Aeronautics & Astronautics reports and utilizes ray tracing to produce the method for starry sky through optical system imaging simulation star chart, when optical surface adopts complicated face shape, programming effort amount is large, and computation process is numerous and diverse.

Summary of the invention

The technical problem to be solved in the present invention there is provided one and carries out imaging by computer simulation optical system of star sensor to stellar field, to obtain the imaging system of digital star chart.

The invention provides a kind of imaging system of computer simulation star sensor stellar field, comprise: observation sing data storehouse, be made up of observation star, described observation star is screen from original star catalogue according to the limiting magnitude of star sensor, that is: only retain double star equivalence magnitude not higher than the double star of limiting magnitude and magnitude not higher than the fixed star beyond the double star of limiting magnitude; The user input set up in ZEMAX optical design software, its optical axis being suitable for the optical module set in ZEMAX optical design software points to, the pixel number of image planes detector and size; Be suitable for the expansion module that described ZEMAX optical design software is called, comprise: extract observation star module, calculate field positions module, calculate pixel gray scale module; The described observation star module field angle corresponding according to the image planes detector in described optical module of extracting is extracted described optical axis in the database and is pointed to observation star in field range, namely extracts the observation star in visual field; The position of the observation star in visual field is transformed into body coordinate system from inertial coordinates system by described calculating field positions module, utilizes described body coordinate system to calculate the field angle of this observation star; And the field angle of described observation star is passed to described optical module as object plane information; ZEMAX optical design software, also comprise ray tracing module, be suitable for after described optical module obtains described object plane information, for the observation star in described visual field, utilize described ray tracing module to complete stellar field imaging, and the position coordinates of the light arrival image planes of observation star and energy value are passed to described calculating pixel gray scale module; Described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives.

Further, in order to calculate described double star equivalence magnitude, this double star equivalence magnitude m ₀computing formula be: make two magnitudes of double star be respectively m ₁and m ₂, namely $m_0=m_1-2.5\lg ({10}^{\frac{m_1-m_2}{2.5}}+1);$ And in order to better extract the observation star in visual field, described observation sing data storehouse also comprises: the asterisk of described observation star, magnitude, right ascension, declination data, described observation star is by declination sequence.

Further, in order to make the digital star chart of output more close to true star chart, described user input also comprises: pseudo-star adds module, is suitable for the pseudo-star needing to add respective numbers according to user; Described expansion module also comprises: simulate pseudo-star module, is suitable for the pseudo-star number of adding module input according to described pseudo-star, produces random point light source to simulate pseudo-star.

Further, on the basis that with the addition of pseudo-star, also to close to true star chart, then need to consider the noise of described star sensor in shooting process to make the digital star chart of output; Therefore described user input also comprises: noise adds, be suitable for the appropriate noise adding star sensor and produce in described digital star chart.

The technical scheme of the imaging system of computer simulation star sensor stellar field of the present invention has the following advantages compared to existing technology: (1) described calculating pixel gray scale module can obtain the star chart data of mating with detector, according to Pixel size and the number of user's input, described calculating pixel gray scale module is to image planes data sampling and quantification, calculate the brightness of each pixel, export the digital star chart mated with detector; (2) programming effort amount is few, and this imaging system make use of the ray tracing function of ZEMAX optical design software, and ZEMAX optical design software is responsible for imaging process, need not consider optical system structure and face type, saved programing work amount in program design; (3) analogy method is simple to operate, is easy to realize, and cost is low; This imaging system has friendly human-computer interaction interface, and user is by dialog box input parameter, and imaging system completes Imaging Simulation, exports digital star chart; Stellar field imaging simulated by existing optical design software platform, does not need high expense; (4) imaging system evaluates the powerful of star sensor system each several part performance.Imaging system can provide data for evaluating the image quality of optical system of star sensor, to checking and improve Performance of Optical System, prediction and avoid pitfalls, save engineering cost and the time significant; This imaging system can for research star sensor obtaining star location, nautical star preferably, importance in star map recognition scheduling algorithm provides abundant simulation star chart data, and check algorithm performance.

The technical problem to be solved in the present invention there is provided one and carries out imaging by computer simulation optical system of star sensor to stellar field, to obtain the formation method of digital star chart.

The invention provides a kind of formation method of computer simulation star sensor stellar field, comprising:

(1) the observation star filtered out from original star catalogue according to the limiting magnitude of star sensor to form observation sing data storehouse, that is: only retain double star equivalence magnitude not higher than the double star of limiting magnitude and magnitude not higher than the fixed star beyond limiting magnitude double star;

(2) in ZEMAX optical design software, set up user input, point to for the optical axis setting optical module in ZEMAX optical design software;

(3) utilize the observation star extracted in observation star module extraction visual field, namely corresponding according to the image planes detector in described optical module field angle extracts the observation star in described optical axis sensing field range in the database; And utilize calculating field positions module that the position of the observation star in visual field is transformed into body coordinate system from inertial coordinates system, utilize described body coordinate system to calculate the field angle of this observation star; And the field angle of described observation star is passed to described optical module as object plane information;

(4) after described optical module obtains described object plane information, for the observation star in described visual field, utilize the ray tracing module in ZEMAX optical design software to complete stellar field imaging, and the position coordinates of the light of the observation star in described visual field arrival image planes and energy value are passed to the calculating pixel gray scale module in described user input;

(5) described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives.

Further, in order to calculate described double star equivalence magnitude, double star equivalence magnitude m in step (1) ₀computing formula be: make two magnitudes of double star be respectively m ₁and m ₂, namely $m_0=m_1-2.5\lg ({10}^{\frac{m_1-m_2}{2.5}}+1);$ And in order to better extract the observation star in visual field, described observation sing data storehouse also comprises: the asterisk of described observation star, magnitude, right ascension, declination data, described observation star is by declination sequence.

Further, in order to make the digital star chart of output more close to true star chart, described user input also comprises: pseudo-star adds module, is suitable for the pseudo-star needing to add respective numbers according to user; Described expansion module also comprises: simulate pseudo-star module, is suitable for the pseudo-star number of adding module input according to described pseudo-star, produces random point light source to simulate pseudo-star; Described pseudo-sing data is added in object plane information in described step (3).

Further, on the basis that with the addition of pseudo-star, also to close to true star chart, then need to consider the noise of described star sensor in shooting process to make the digital star chart of output; Therefore described user input also comprises: noise adds, be suitable for the appropriate noise adding star sensor and produce in the digital star chart of described step (5).

The technical scheme of the formation method of computer simulation star sensor stellar field of the present invention has the following advantages compared to existing technology: (1) described calculating pixel gray scale module can obtain the star chart data of mating with detector, according to Pixel size and the number of user's input, described calculating pixel gray scale module is to image planes data sampling and quantification, calculate the brightness of each pixel, export the digital star chart mated with detector; (2) programming effort amount is few, and this formation method make use of the ray tracing function of ZEMAX optical design software, and ZEMAX optical design software is responsible for imaging process, need not consider optical system structure and face type, saved programing work amount in program design; (3) analogy method is simple to operate, is easy to realize, and cost is low; This formation method has friendly human-computer interaction interface, and user is by dialog box input parameter, and formation method completes Imaging Simulation, exports digital star chart; Stellar field imaging simulated by existing optical design software platform, does not need high expense; (4) formation method evaluates the powerful of star sensor system each several part performance.Formation method can provide data for evaluating the image quality of optical system of star sensor, to checking and improve Performance of Optical System, prediction and avoid pitfalls, save engineering cost and the time significant; This formation method can for research star sensor obtaining star location, nautical star preferably, importance in star map recognition scheduling algorithm provides abundant simulation star chart data, and check algorithm performance.

Accompanying drawing explanation

In order to make content of the present invention be more likely to be clearly understood, below basis specific embodiment and by reference to the accompanying drawings, the present invention is further detailed explanation, wherein

Fig. 1 is computer simulation star sensor stellar field Irnaging procedures figure;

Fig. 2 is the rotation relationship figure of inertial coordinates system and body coordinate system;

Fig. 3 is the schematic diagram of calculating observation star position in current field;

In Fig. 4 (a) be optical axis point to right ascension and declination be respectively α _c=36.68 °, δ _cwhen=22.87 ° obtain simulation star chart, (b) be optical axis point to right ascension and declination be respectively α _c=30.86 °, δ _cthe simulation star chart of=72.42 °;

In Fig. 5, (a) schemes (a) corresponding star chart with SkyChart Software Create in Fig. 4; B () schemes (b) corresponding star chart with SkyChart Software Create in Fig. 4.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in detail:

Embodiment illustrates: ZEMAX optical design software is for Optical System Design, as the analysis of camera lens and illuminator.It can be used for design and analysis optical system.ZEMAX optical design software can operative norm sequence optical element ray tracing, and discontinuous optical element parasitic light is followed the trail of, and physical optics beam propagation.It can also simulate ray by optical element, as the propagation of camera lens (comprising aspheric surface and gradient-index lens), catoptron, diffraction optical element etc.ZEMAX optical design software also can the effect of analog element surface optics film, and can produce various standard analysis chart.It comprises abundant camera lens storehouse.Physical optics transfer function, can be used for the problem must considering diffraction, as laser beam propagation, holographic, and single-mode fiber optically-coupled.ZEMAX optical design software has powerful optimization tool external member, can be used for camera lens Automatic Optimal adjustment parameter to improve performance to greatest extent reducing aberration, and has abundant tolerance properties.So ZEMAX optical design software comprises: optical module, ray tracing module.

The imaging system of computer simulation stellar field is primarily of expansion module and ZEMAX optical design software two parts composition.Described expansion module is set up according to the expansion programming rule of optical design software ZEMAX, is added in the installation directory of ZEMAX optical design software, accepts it and calls rear display human-computer interaction interface, be i.e. described user input.

Embodiment 1

A kind of imaging system of computer simulation star sensor stellar field on the basis that embodiment illustrates, comprise: observation sing data storehouse (Observedstarcatalog, be designated as OSC star storehouse), be made up of observation star, described observation star is screen from original star catalogue according to the limiting magnitude of star sensor, that is: only retain double star equivalence magnitude not higher than the double star of limiting magnitude and magnitude not higher than the fixed star beyond the double star of limiting magnitude; Wherein said double star equivalence magnitude m ₀computing formula be: make two magnitudes of double star be respectively m ₁and m ₂, namely $m_0=m_1-2.5\lg ({10}^{\frac{m_1-m_2}{2.5}}+1)---\left(1\right)$

The user input set up in ZEMAX optical design software, its optical axis being suitable for the optical module set in ZEMAX optical design software points to, the pixel number of image planes detector and size; Be suitable for the expansion module that described ZEMAX optical design software is called, comprise: extract observation star module, calculate field positions module, calculate pixel gray scale module; The described observation star module field angle corresponding according to the image planes detector in described optical module of extracting is extracted described optical axis in the database and is pointed to observation star in field range, namely extracts the observation star in visual field; The position of the observation star in visual field is transformed into body coordinate system from inertial coordinates system by described calculating field positions module, utilizes described body coordinate system to calculate the field angle of this observation star; And the field angle of described observation star is passed to described optical module as object plane information; ZEMAX optical design software, also comprise ray tracing module, be suitable for after described optical module obtains described object plane information, for the observation star in described visual field, utilize described ray tracing module to complete stellar field imaging, and the position coordinates of the light arrival image planes of observation star and energy value are passed to described calculating pixel gray scale module; Described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives.

The method extracting observation star and their field positions of calculating (i.e. field angle) in this invention can adopt celestial sphere zone method, see paper the method for observed stars extraction " in a kind of star image simulation ", periodical: optical precision engineering, in April, 2004, the 12nd volume, the 2nd phase.

Described observation sing data storehouse also comprises: the asterisk of described observation star, magnitude, right ascension, declination data.

Press declination sequence for the ease of extracting observation star and calculating their field positions (i.e. field angle) described observation star, then the method extracting observation star and their field positions of calculating (i.e. field angle) comprises:

First, (α is pointed to for selected optical axis _c, δ _c), the inertial coordinate (α, δ) picked out in described observation sing data storehouse meets

|δ-δ _c|≤w _m(2)

Star, wherein w _mrepresent the field angle that described image planes detector diagonal line is corresponding.

Formula (2) limits the upper and lower bound that current optical axis points to observation star declination in field range.Because declination δ span is-90 ° ~ 90 °, work as δ _c-w _mwhen being less than-90 °, lower limit should being set and being-90 °, similarly, work as δ _c+ w _mwhen being greater than 90 °, the upper limit should be set to 90 °, namely

Sort, by dichotomy method determination declination value just greater than δ by declination in described observation sing data storehouse _botthe position of star, then reads subsequent data, extracts observation star, until declination value is greater than δ _top.

Then, the position of observation star is transformed into body coordinate system from inertial coordinates system.If the direction cosine vector of observation star S in inertial coordinates system and body coordinate system is respectively V _i, V _b.(α is pointed to for optical axis _c, δ _c), body coordinate system can be obtained by certain way rotatory inertia coordinate system.As shown in Figure 2, inertial coordinates system first around Z axis by+X axis+Y-axis rotation alpha _c, obtain X ' Y ' Z ' coordinate system, new coordinate system again around Y ' axle by+Z ' axially+X ' axle half-twist-δ _c, " coordinate system, this coordinate system is around Z " axle rotates φ to obtain X " Y " Z, obtains body coordinate system X _by _bz _b, the direction cosine vector V of star in body coordinate system can be observed _bfor

$\left[\begin{array}{c}{V}_{\mathrm{bx}}\\ V_{\mathrm{by}}\\ V_{\mathrm{bz}}\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\φ}& \sin \mathrm{\φ}& 0\\ -\sin \mathrm{\φ}& \cos \mathrm{\φ}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}\cos (90-{\mathrm{\δ}}_c)& 0& -\sin (90-{\mathrm{\δ}}_c)\\ 0& 1& 0\\ \sin (90-{\mathrm{\δ}}_c)& 0& \cos (90-{\mathrm{\δ}}_c)\end{array}\right]\×$

$\left[\begin{array}{ccc}{\cos \mathrm{\α}}_c& {\sin \mathrm{\α}}_c& 0\\ {-\sin \mathrm{\α}}_c& {\cos \mathrm{\α}}_c& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{c}\cos \mathrm{\α}\cos \mathrm{\δ}\\ \sin \mathrm{\α}\cos \mathrm{\δ}\\ \sin \mathrm{\δ}\end{array}\right]---\left(4\right)$

Wherein φ is by body coordinate system X _b, Y _bthe actual sensing of axle determines, when getting X _baxle and warp is tangent, point to the direction that declination reduces, Y _btangent with parallel, when pointing to direction that right ascension increases, φ=0.

Finally, the field angle of calculating observation star, and determine whether Current observation star appears in visual field.As Fig. 3, observation star is at X _b, Y _bfield angle XFLD on direction, YFLD are

$\mathrm{XFLD}=-{\mathrm{tg}}^{-1}\left(\frac{V_{\mathrm{bx}}}{V_{\mathrm{bz}}}\right),$ $\mathrm{YFLD}=-{\mathrm{tg}}^{-1}\left(\frac{V_{\mathrm{by}}}{V_{\mathrm{bz}}}\right)---\left(5\right)$

If optical system is at X _b, Y _bmaximum field of view angle on direction is w _aand w _b, only have satisfied

|XFLD|≤w _A/2、|YFLD|≤w _B/2(6)

Fixed star just can be observed.Through type (6) screens the observation star obtained in current field, also obtains their field angle XFLD, YFLD at this moment simultaneously.

For star sensor, pseudo-star with truly observe star there is no significant difference.Described user input also comprises: pseudo-star adds module, is suitable for the pseudo-star needing to add respective numbers according to user; Described expansion module also comprises: simulate pseudo-star module, is suitable for the pseudo-star number of adding module input according to described pseudo-star, produces random point light source to simulate pseudo-star, they joined on the object plane of optical system, then with the mode imaging of similar observation star.

ZEMAX optical design software, by ray tracing, completes imaging, and the position coordinates (x, y) of light arrival image planes and energy f (x, y) are passed to expansion module.

Concrete grammar is, utilizes the ray tracing function of ZEMAX optical design software to complete stellar field imaging.For every observation star in current field, in spectral range, make ray tracing, obtain them through optical system imaging.Every root light represents a energy, and light should be uniformly distributed, and entrance pupil is pressed square net and divides, and the light chosen through entrance pupil center and entrance pupil internal net point participates in imaging.

Through ray tracing, the position coordinates that light arrives image planes is (x, y).Star sensor CCD or APS detector receive star image, and detector take pixel as elementary cell, and image planes are discrete through over-sampling.The detector pixel that light reaches is determined by (x, y).

Consider brightness and the detector spectral response characteristic of observation star, need arrange weights W m and the Ww of light, the brightness that wherein Wm is corresponding with fixed star is directly proportional, and Ww is directly proportional to detector spectral response.Supposing that observation star sends the gross energy being full of entrance pupil light is 1, and total light number is nray, and during certain root light arrival image planes, energy attenuation is η times, and energy when arriving image planes is η WmWw/nray.By arriving the energy accumulation of same pixel position light, obtain the light intensity on this pixel in star chart.

Also comprise in expansion module and calculate pixel gray scale module, it calculates the gray scale of each pixel in star chart, adds the setting noise of described user input simultaneously, exports digital star chart.

For storing the star image data of each pixel, need define a matrix variables matched with image planes detector size, each element of matrix stores the star image information of corresponding pixel respectively.But star image region only accounts for the sub-fraction of image planes, most of region of star chart is dark, the most elements data value of this matrix is 0, and do not use in computation process, use tlv triple structure sparse matrix to store star chart data, to save memory storage space for this reason.Tlv triple structure is defined as follows,

typedefstruct{intcol,row;floatvalue;}Triple;(7)

Wherein row, col, value record respectively non-zero element in matrix line number, row number, numerical value.Whole star chart is stored in the structure of following formula definition,

typedefstruct{Tripledata[MAXSIZE+1];

intm，n,t;}starmap;(8)

Wherein MAXSIZE is a predefined constant, and star image pixel number is no more than MAXSIZE at most, and data records position and the gray scale of each star image pixel, and m, n are total line number of star chart and total columns, and t is the total pixel number of star image.

Sparse matrix starmap exports according to BMP bitmap format.The gray scale span of each pixel is 0-255, namely 8.The gray-scale value setting in current star chart most bright image unit is 255, and other pixel processes by the ratio ruleization of its gray scale with most bright image unit gray scale.

The stellar field Imaging Simulation program interface of the imaging system of computer simulation star sensor stellar field of the present invention, comprises star chart display window, text window, interactive dialogue frame etc.Described user input is convenient to artificial participation and is changed parameter value, as optical axis sensing, field angle, the distribution of light form for trace, image planes detector size, and Pixel size, and pseudo-star number, the parameters such as noise interpolation." InputStarFile " text box allows user to select observation sing data library file, and program is to the star simulation imaging in database.Can select to show desirable star chart by " ShowAs " drop-down menu and still simulate star chart.When selecting " Idealstarmap ", the coordinate position on the resonable imagination face of program computation each observation star, each star image occupies a pixel in image planes.When selecting " Simulationmap ", obtain simulation star chart data.Star chart, by import file name in " OutputFile " text box in interface, is saved as the BMP bitmap file of given filename, to facilitate subsequent processes by user after advising process performs and terminates.

By setting Monte Carlo simulation program (namely setting optical axis immediately to point to) accordingly, the random sensing simulation star chart specified number can also be produced, and with BMP file output, filename numbers in order.

After program performs, user can select text display manner to check right ascension and the declination value of random sensing, and true star number and pseudo-star number in star chart, also can export position XFLD, the YFLD in the asterisk of observation star in current field, magnitude, visual field as required, the data such as desirable star image image coordinates.

Embodiment 2

The formation method of a kind of computer simulation star sensor stellar field on the basis of embodiment 1, comprising:

(1) the observation star filtered out from original star catalogue according to the limiting magnitude of star sensor to form observation sing data storehouse, that is: only retain double star equivalence magnitude not higher than the double star of limiting magnitude and magnitude not higher than the fixed star beyond limiting magnitude double star;

(2) in ZEMAX optical design software, set up user input, point to for the optical axis setting optical module in ZEMAX optical design software;

(3) utilize the observation star extracted in observation star module extraction visual field, namely corresponding according to the image planes detector in described optical module field angle extracts the observation star in described optical axis sensing field range in the database; And utilize calculating field positions module that the position of the observation star in visual field is transformed into body coordinate system from inertial coordinates system, utilize described body coordinate system to calculate the field angle of this observation star; And the field angle of described observation star is passed to described optical module as object plane information;

(4) after described optical module obtains described object plane information, for the observation star in described visual field, utilize the ray tracing module in ZEMAX optical design software to complete stellar field imaging, and the position coordinates of the light of the observation star in described visual field arrival image planes and energy value are passed to the calculating pixel gray scale module in described user input;

(5) described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives.

Double star equivalence magnitude m in step (1) ₀computing formula be: make two magnitudes of double star be respectively m ₁and m ₂, namely $m_0=m_1-2.5\lg ({10}^{\frac{m_1-m_2}{2.5}}+1);$

Described observation sing data storehouse also comprises: the asterisk of described observation star, magnitude, right ascension, declination data, and described observation star is by declination sequence.

Described user input also comprises: pseudo-star adds module, is suitable for the pseudo-star needing to add respective numbers according to user; Described expansion module also comprises: simulate pseudo-star module, is suitable for the pseudo-star number of adding module input according to described pseudo-star, produces random point light source to simulate pseudo-star; Described pseudo-sing data is added in object plane information in described step (3).

Described user input also comprises: noise adds, and is suitable for the appropriate noise adding star sensor and produce in the digital star chart of described step (5).

Embodiment 3

On the basis of embodiment 1 and 2, generate the concrete setting of digital star chart, and digital star chart and actual star chart are compared.

In ZEMAX optical design software, arrange perfect optical system, getting field angle is 20 ° × 20 °, and bore is 27.3mm, focal length is 43.56mm, the parameter in each face of optical system is as shown in table 1, image planes out of focus 0.07mm, now with the star image energy comprising 90% in 1.5 pixels circle that is radius.And set limiting magnitude as 5.2 etc., detector pixel number is 1024 × 1024.

Table 1 perfect optical system parameter (unit mm)

Surface	Type	Radius	Thickness	Semi-diameter
					OBJ	Standard	Infinity	Infinity	Infinity
Stop	Standard	Infinity	43.56	13.65
					3	Paraxial	Infinity	43.56	21.33
4	Standard	Infinity	0.07	7.6808
					IMAG	Standard	Infinity		7.7070

The two width simulation star charts obtained when optical axis points to and is respectively (36.68 °, 22.87 °) and (30.86 °, 72.42 °), as shown in Figure 4.Fig. 4 (a) is not for adding the simulation star chart of pseudo-star and noise, and Fig. 4 (b) is for adding the simulation star chart after two pseudo-stars.Fig. 5 is the corresponding star chart with SkyCharts Software Create.

The star being numbered 13 in Fig. 4 (a) is a double star.Be numbered in Fig. 5 (a) 14 fixed star and Fig. 5 (b) in be numbered 12,13,14 fixed star be respectively 5.4,5.3,5.3 and 5.5 at SAO star catalogue culminant star etc., and magnitude is less than 5.2 etc. in the star catalogue adopted at SkyCharts, therefore do not occur in the diagram.Comparison diagram 4 and Fig. 5, visible, analog result and SkyCharts star chart are more or less the same.

Table 2,3 gives the observation star image position that star is obtained by perfect optical system imaging, and by the star image position that obtaining star location algorithm process star chart obtains, for simplicity, is called ideal position and measuring position.The RMS value of measuring position and ideal position error is respectively 0.165,0.056 pixel in x and y direction.Include image planes in these errors to sample the error of the error that causes and obtaining star location algorithm.

Adopt position and the gray scale of star image pixel in sparse matrix record two width simulation star chart, only store the data of 210,179 pixels respectively, compared to using the matrix of corresponding 1024 × 1024 total pixel numbers to store these data, the memory headroom that simulation star chart uses is about original 2/10000ths.

Above result shows, based on ZEMAX optical design software, by program design, the imaging of simulation stellar field is practicable.

Star chart star image data simulated by table 2 Fig. 4 (a)

Star chart star image data simulated by table 3 Fig. 4 (b)

Obviously, above-described embodiment is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments.And these belong to spirit institute's apparent change of extending out of the present invention or change and are still among protection scope of the present invention.

Claims (1)

1. a formation method for computer simulation star sensor stellar field, comprising:

(1) the observation star filtered out from original star catalogue according to the limiting magnitude of star sensor to form observation sing data storehouse, that is: only retain double star equivalence magnitude not higher than the double star of limiting magnitude and magnitude not higher than the fixed star beyond limiting magnitude double star;

(2) in ZEMAX optical design software, set up user input, point to for the optical axis setting optical module in ZEMAX optical design software;

(3) utilize the observation star extracted in observation star module extraction visual field, namely corresponding according to the image planes detector in described optical module field angle extracts the observation star in described optical axis sensing field range in the database; And utilize calculating field positions module that the position of the observation star in visual field is transformed into body coordinate system from inertial coordinates system, utilize described body coordinate system to calculate the field angle of this observation star; And the field angle of described observation star is passed to described optical module as object plane information; The concrete grammar of the field angle of calculating observation star is as follows: first, points to (α for selected optical axis _c, δ _c), the inertial coordinate (α, δ) picked out in described observation sing data storehouse meets

|δ-δ _c|≤w _m(2)

Star, wherein w _mrepresent the field angle that described image planes detector diagonal line is corresponding;

Then, the position of observation star is transformed into body coordinate system from inertial coordinates system; If the direction cosine vector of observation star S in inertial coordinates system and body coordinate system is respectively V _i, V _b, so observe the direction cosine vector V of star in body coordinate system _bfor

$0\begin{array}{c}\left[\begin{array}{c}{V}_{\mathrm{bx}}\\ V_{\mathrm{by}}\\ b_{\mathrm{bz}}\end{array}\right]=\left[\begin{array}{ccc}\cos \mathrm{\φ}& \sin \mathrm{\φ}& 0\\ -\sin \mathrm{\φ}& \cos \mathrm{\φ}& 0\\ 0& 0& 0\end{array}\right]\left[\begin{array}{ccc}\cos (90-{\mathrm{\δ}}_c)& 0& -\sin (90-{\mathrm{\δ}}_c)\\ 0& 1& 0\\ \sin (90-{\mathrm{\δ}}_c)& 0& \cos (90-{\mathrm{\δ}}_c)\end{array}\right]\×\\ \left[\begin{array}{ccc}\cos {\mathrm{\α}}_c& \sin {\mathrm{\α}}_c& 0\\ -\sin {\mathrm{\α}}_c& \cos {\mathrm{\α}}_c& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{c}\cos \mathrm{\α}\cos \mathrm{\δ}\\ \sin \mathrm{\α}\cos \mathrm{\δ}\\ \sin \mathrm{\δ}\end{array}\right]\end{array}---\left(4\right);$

Finally, the field angle of calculating observation star, and determine whether Current observation star appears in visual field; Observation star is at X _b, Y _bfield angle XFLD on direction, YFLD are

$\mathrm{XFLD}=-t{g}^{-1}\left(\frac{V_{\mathrm{bx}}}{V_{\mathrm{bz}}}\right),\mathrm{YFLD}=-t{g}^{-1}\left(\frac{V_{\mathrm{by}}}{V_{\mathrm{bz}}}\right)---\left(5\right)$

If optical system is at X _b, Y _bmaximum field of view angle on direction is w _aand w _b, only have satisfied

|XFLD|≤w _A/2、|YFLD|≤w _B/2(6)

Fixed star just can be observed; Through type (6) screens the observation star obtained in current field, also obtains their field angle XFLD, YFLD at this moment simultaneously;

(4) after described optical module obtains described object plane information, for the observation star in described visual field, the ray tracing module in ZEMAX optical design software is utilized to complete stellar field imaging, for every observation star in current field, in spectral range, make ray tracing, obtain them through optical system imaging; Every root light represents a energy, and light should be uniformly distributed, and entrance pupil is pressed square net and divides, and the light chosen through entrance pupil center and entrance pupil internal net point participates in imaging; And the calculating pixel gray scale module position coordinates of the light of the observation star in described visual field arrival image planes and energy value passed in described user input;

(5) described calculating pixel gray scale module exports digital star chart according to the pixel number of described image planes detector of setting, size and the energy value that receives.