CN101236090A - Moon-tracking segment ultraviolet sensor earth and moon photography time predication method - Google Patents

Abstract

The invention discloses a time prediction method for earth-moon picture shooting by an ultraviolet sensor at cislunar fight, which comprises steps of (1) selecting an orbit arc meeting the light condition for earth-moon shooting, (2) selecting an orbit arc, in which earth-moon appears, within viewing field area of the ultraviolet sensor, (3) taking the orbit position simultaneously meeting the step (1) and the step (2) as a selectable orbit for shooting, inputting an orbit prediction position corresponding to the selectable orbit, attitude matrix at a certain time before the selectable orbit, sun-moon-earth ephemeredes and a satellite attitude motion model after launching the satellite and before the coming of the selectable orbit, calculating the attitude matrix and a selenocentric/geocentric vector within the prediction time period and making a curve, changing along the time, of an included angle of the selenocentric/geocentric vector and a viewing field central vector, then obtaining continuous visible time range(t1-t2) of earth/moon by the curve and the size of the viewing field of the ultraviolet sensor and calculating the best time according to the obtained continuous visible time range.

Description

The moon-tracking segment ultraviolet sensor earth and moon photography time predication method

Technical field

The present invention relates to a kind of Benyue section and adopt ultraviolet sensors to carry out the method for ground month time predication, belong to optical imagery attitude sensor field.

Background technology

Along with the quick progress of imaging detection device and processor technology, the spacecraft attitude sensor is developed to imaging type by the unit scan formula gradually, and ultraviolet sensors is exactly a kind of big view field imaging formula attitude sensor that is different from traditional horizon instrument.

Ultraviolet sensors possesses the ability that the Benyue section is obtained the ultraviolet earth, ultraviolet moon image, not only important value but also utilization are obtained on science data the ground moon image information and cooperate the inertia attitude for realizing that independent navigation has important value.

At first ultraviolet sensors has special combined type visual field distribution, and the celestial sphere that forms distinguish covers, and therefore needs analysis ultraviolet sensors visual field model; The earth, the moon belong to the reflected sunlight imaging in addition, and shooting condition also needs certain sun, the earth/moon, satellite position demand; Also have, predict that the moon/earth appears at the imaging that the short accurate prediction that needs the shooting point moment of time visual field in could realize the earth/moon certainly not influencing under the satellite motion mode state to take to change next step motion of satellite and attitude.

Ultraviolet sensors itself is a brand-new imaging type attitude sensor, and this patent content is the expanded application research of carrying out on the ultraviolet sensors basis.In addition, the Benyue section is utilized ultraviolet sensors to carry out the moon/earth technique for taking and is verified it also is a new task, and has passed through in the rail flight test.Utilize ultraviolet sensors that the accurate prediction algorithm of the moon/earth shooting time be there is no domestic and international report.

External techwatch [J], 2006 the 9th phases, talk about Smart-1 in " No. 1, first lunar excursion module wisdom of Europe " and utilize the high precision camera moon to be carried out imaging, but do not specify segmental arc selection criterion, the best prediction mode method constantly of taking in the Benyue section.

A elfving, L Stagnearo, A Winton, introduced the situation that the Benyue section moon is taken camera that is used among the SMART-1:Key technologies andautonomy implementations.Acta Astronautic 52 (2003), not enough system of selection at undeclared shooting segmental arc, best shooting time.

U.S. Pat 5319969 has been introduced a kind of three-axis attitude of ultraviolet spectral coverage attitude sensor that utilizes in the title " Method for determining 3-axis spacecraftattitude " and has been determined method, does not wherein relate to the shooting forecasting problem of Benyue section.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of moon-tracking segment ultraviolet sensor earth and moon photography time predication method is provided, this method is taken ground month ultraviolet image according to the ground transmission instruction that predicts the outcome in the best time, reaches not change the shooting of satellite motion pattern realization to the earth/moon.

Technical solution of the present invention is: the moon-tracking segment ultraviolet sensor earth and moon photography time predication method comprises the following steps:

(1) carries out the illumination analysis according to a solar vector and a month heart vector in nominal track, the satellite body system, select the track segmental arc of taking illumination condition by the moon contentedly;

(2) obtain to satisfy the earth under the orbital arc fragment position in the step (1)/moon heart vector set according to the Satellite Attitude Movement of design in advance, whether in described vector set have vector be present in ultraviolet sensors field of view in, select to satisfy the track segmental arc in the ultraviolet sensors field of view if judging;

(3) will satisfy the orbital position of step (1) and step (2) simultaneously as taking optional track, before described optional track arrives, import the predicted orbit position of described optional track correspondence, optional track a certain moment attitude matrix, life ground ephemeris and Satellite Attitude Movement model before after the satellites transmits; Calculate attitude matrix, month heart/the earth's core vector in the predicted time section, and make a moon heart/the earth's core vector and the time dependent curve of visual field center vector angle, obtain the visible time range [t of the continuous earth/moon by curve and ultraviolet sensors visual field size ₁～t ₂], according to the continuously visible time range calculating optimum that obtains constantly.

Illumination analytic process in the described step (1) is: calculate solar vector V _SWith moon heart vector V _MOr the earth's core vector V _EBetween angle , computing formula is:

＝acos(V _S·V _i)，

As ＞ _T, think under this orbital position that contentedly month taking an illumination condition obtains the better phases of the moon; Wherein, V _iRepresent a month heart vector V _MOr the earth's core vector V _E

 _TBe the angle threshold value, size is determined according to the shooting demand.

The computing formula of attitude matrix is in the described step (3):

C _t＝R _t·C ₀

Wherein, R _tBe the posture changing matrix, determine according to the Satellite Attitude Movement model;

C ₀A certain moment attitude matrix for input.

Calculating month heart/the earth's core vector formula in the described step (3) is:

M _t＝R _t·M ₀

E _t＝R _t·E ₀

Wherein, M _t-t moon heart vector constantly;

E _t-t the earth's core vector constantly;

R _tBe the posture changing matrix, determine according to the Satellite Attitude Movement model;

M ₀The a certain moment t of-input ₀Corresponding moon heart vector.

Visible time range deterministic process is as follows in the described step (3):

At first, calculate t moon heart vector M constantly _tWith the earth's core vector E _tThe angle  of the center vector Fs of ultraviolet sensors visual field, computing formula is:

 _M(t)＝acos(Fs·M _t)

 _E(t)＝acos(Fs·E _t)

Then, with the value and the visual field threshold value T of curve correspondence _FOVCompare, work as  _M＜T _FOV, the moon is described as seen, otherwise invisible; Work as  _E＜T _FOV, the earth is described as seen, otherwise invisible; Continuous visible time border is visible time range; Wherein, T _FOVEqual the visual field size of ultraviolet sensors optical system for the visual field threshold value.

The best time is got described visible time range [t in the described step (3) ₁～t ₂] intermediate value, or [t ₁～t ₂] the angle  moment corresponding of time range minimum.

The present invention compared with prior art beneficial effect is:

(1) the technology of the present invention is divided into ground moon bat figure prediction the preceding track selection work of emission and launches back prediction work in time, and according to field angle optimum shooting point is predicted, solved the problem of utilizing the success of ultraviolet sensors Benyue stage to take the earth, the moon at rail.

(2) the present invention carries out the illumination analysis by the angle that calculates between solar vector and month heart vector/the earth's core vector, has guaranteed that the moon/earth image possesses higher image-forming condition and science construction value in the selected shooting segmental arc.

(3) the present invention utilizes the method in a moon heart/the earth's core vector and visual field center vector angle analysis means acquisition continuous imaging interval to have and calculates simple, complete advantage.

(4) the technology of the present invention angle method placed in the middle or minimum service time can obtain optimum shooting moment point, guarantees to photograph the moon/earth and can photograph optimal image.

Description of drawings

Fig. 1 is the technology of the present invention algorithm flow chart;

Fig. 2 is an embodiment of the invention moon heart vector and visual field center vector angle curve;

Fig. 3 for the embodiment of the invention moon heart vector be in the visual field inner curve continuously;

Fig. 4 takes emulating image for our bright embodiment.

Embodiment

It is disclosed a kind of three-axis attitude sensor that utilizes the ultraviolet spectral coverage in the US5837894 title " Wide Field of View Sensor with diffractive OpticalCorrector " that the ultraviolet sensors that relates among the present invention can adopt the patent No. of Honeywell company application.Can also adopt disclosed a kind of three-axis attitude sensor that utilizes the ultraviolet spectral coverage in U.S. Pat 5319969 titles " Method for determining 3-axis spacecraft attitude ".

Below the moon is taken pictures and specifically describe for example.

As shown in Figure 1, be method flow diagram of the present invention, following mask body is introduced the implementation procedure of this method.

(1) according to the nominal track (X, Y, Z), solar vector and a month heart vector carry out the illumination analysis in the satellite body system, select to satisfy the track segmental arc that the earth/moon is taken illumination condition;

The illumination analytic process is: according to solar vector V _S, month heart vector V _MCalculate angle β:

β＝acos(V _S·V _M)

As β＞β _T, think that satisfying illumination condition under this orbital position obtains better lunar map picture, β _TFor the phase angle threshold value is selected according to demand, 90 ° of corresponding crescent or half moons wherein, and generally require greater than 30 ° otherwise can only see very little crescent moon, the embodiment threshold value is selected 30 °.

(2) obtain to satisfy the earth under the orbital arc fragment position in the step (1)/moon heart vector set according to the Satellite Attitude Movement of design in advance, whether in described vector set have vector be present in ultraviolet sensors field of view in, select to satisfy the track segmental arc in the ultraviolet sensors field of view if judging;

Whether in described vector set have vector be present in ultraviolet sensors field of view in, method is for judging vector and visual field center vector F if judging _sAngle  whether less than field angle, select the orbital position of the vector correspondence in the ultraviolet sensors field of view;

(3) orbital position that will satisfy step (1) and step (2) simultaneously before described optional track arrives, is imported the predicted orbit position of described optional track correspondence, optional track a certain moment t before as taking optional track after the satellites transmits ₀Attitude matrix, life ground ephemeris and Satellite Attitude Movement model; Calculate attitude matrix, month heart/the earth's core vector in the predicted time section, and make a moon heart/the earth's core vector and the time dependent curve of visual field center vector angle, obtain the visible time range [t of the continuous earth/moon by curve and ultraviolet sensors visual field size ₁～t ₂], according to the continuously visible time range calculating optimum that obtains constantly.

Moon heart vector V under the body series _M:

x_moon＝-0.6802； y_moon＝0.3213； z_moon＝-0.6589；

Solar vector V _S:

x_sun＝1； y_sun＝0； z_sun＝0；

A solar vector and a month heart vector angle β:

β＝acos(V _M·V _S)＝132.86°

As seen angle is much larger than 30 °, is between crescent or half moon and the full moon to show as gibbous moon.

According to t ₀Attitude matrix C ₀Calculate predicted time interval [t ₀～t _n] corresponding attitude matrix C _t:

C _t＝R _t·C ₀

R wherein _tBeing the posture changing matrix, is to be determined by the Satellite Attitude Movement model, sets satellite in the utilization example to center on+the X-axis rotation, and speed is that 0.1 °/s is designated as V, selects predicted time length t _L=t _n-t ₀Be 1 hour, remember t among the embodiment _n=3600s, t ₀=Os, R _tFor:

$R_t=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\θ}& \sin \mathrm{\θ}\\ 0& -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]$

Rotate then around+Y-axis if select:

$R_t=\left[\begin{array}{ccc}\cos \mathrm{\θ}& 0& -\sin \mathrm{\θ}\\ 0& 1& 0\\ \sin \mathrm{\θ}& 0& \cos \mathrm{\θ}\end{array}\right]$

Rotate then around+Z axle if select:

$R_t=\left[\begin{array}{ccc}\cos \mathrm{\θ}& \sin \mathrm{\θ}& 0\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}& 0\\ 0& 0& 1\end{array}\right]$

In the formula: θ=(t-t ₀) * V

According to posture changing matrix R _tObtain the moon heart vector V under the moment t _MtWith the earth's core vector V _Et

M _t＝R _t·M ₀

E _t＝R _t·E ₀

Calculate a month heart vector M _tThe earth's core vector E _tAngle  with the centre normal Fs of visual field

 _M＝acos(Fs·M _t)

 _E＝acos(Fs·E _t)

 _M＜T _FOVThe moon as seen, and is otherwise invisible

 _E＜T _FOVThe earth as seen, and is otherwise invisible

T _FOVVisual field size for visual field threshold value Here it is sensor optical system is set at 10 ° in the example.The Fs value is as follows among the embodiment:

x_Fs＝0 y_Fs＝0 z_Fs＝1

Predicted time is selected 1 hour, and the angle curve at month heart vector and center, visual field is seen Fig. 2 in the predicted time that calculates so, and Fig. 3 is seen less than 10 ° curve in the visual field continuously in the search back, obtains the time:

t ₁＝2510(s) t ₂＝2760(s)

The best time t then _Optimal:

Have according to time average:

$t_{\mathrm{optimal}}=\frac{t_2+t_1}{2}$ t _optimal＝2635(s)

[t ₁～t ₂] minimum angle  is constantly corresponding for time range:

t _optimal＝{t| _t＝min()} t _optimal＝2640(s)

As seen predicted time is very approximate under two standards, and the corresponding analogous diagram of taking of time average is seen Fig. 4.

Inventive concept and method can be applied in the time prediction of other space sensitive device, as long as the method for utilizing thought of the present invention to realize all falls into protection scope of the present invention, the unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (6)

1, moon-tracking segment ultraviolet sensor earth and moon photography time predication method is characterized in that comprising the following steps:

(1) carries out the illumination analysis according to a solar vector and a month heart vector in nominal track, the satellite body system, select the track segmental arc of taking illumination condition by the moon contentedly;

(2) obtain to satisfy the earth under the orbital arc fragment position in the step (1)/moon heart vector set according to the Satellite Attitude Movement of design in advance, judge whether described vector set is present in the ultraviolet sensors field of view, select to satisfy the track segmental arc in the ultraviolet sensors field of view;

(3) will satisfy the orbital position of step (1) and step (2) simultaneously as taking optional track, before described optional track arrives, import the predicted orbit position of described optional track correspondence, optional track a certain moment attitude matrix, life ground ephemeris and Satellite Attitude Movement model before after the satellites transmits; Calculate attitude matrix, month heart/the earth's core vector in the predicted time section, and make a moon heart/the earth's core vector and the time dependent curve of visual field center vector angle, obtain the visible time range [t of the continuous earth/moon by curve and ultraviolet sensors visual field size ₁～t ₂], according to the continuously visible time range calculating optimum that obtains constantly.

2, moon-tracking segment ultraviolet sensor earth and moon photography time predication method according to claim 1 is characterized in that: the illumination analytic process in the described step (1) is: calculate solar vector V _SWith moon heart vector V _MOr the earth's core vector V _EBetween angle , computing formula is:

＝acos(V _S·V _i)

As ＞ _T, think under this orbital position that contentedly month taking an illumination condition obtains the better phases of the moon;

Wherein, V _iRepresent a month heart vector V _MOr the earth's core vector V _E

 _TBe the angle threshold value, size is determined according to the shooting demand.

3, moon-tracking segment ultraviolet sensor earth and moon photography time predication method according to claim 1 is characterized in that: the computing formula of attitude matrix is in the described step (3):

C _t＝R _t·C ₀

Wherein, R _tBe the posture changing matrix, determine according to the Satellite Attitude Movement model;

C ₀A certain moment attitude matrix for input.

4, moon-tracking segment ultraviolet sensor earth and moon photography time predication method according to claim 1 is characterized in that: calculating month heart/the earth's core vector formula in the described step (3) is:

M _t＝R _t·M ₀

E _t＝R _t·E ₀

Wherein, M _t-t moon heart vector constantly;

E _t-t the earth's core vector constantly;

R _tBe the posture changing matrix, determine according to the Satellite Attitude Movement model;

M ₀The a certain moment t of-input ₀Corresponding moon heart vector.

5, moon-tracking segment ultraviolet sensor earth and moon photography time predication method according to claim 1 is characterized in that: visible time range deterministic process is as follows in the described step (3):

At first, calculate t moon heart vector M constantly _tWith the earth's core vector E _tWith the angle  of the center vector Fs of ultraviolet sensors visual field, computing formula is:

 _M(t)＝acos(Fs·M _t)

 _E(t)＝acos(Fs·E _t)

Then, with the value and the visual field threshold value T of curve correspondence _FOVCompare, work as  _M＜T _FOV, the moon is described as seen, otherwise invisible; Work as  _E＜T _FOV, the earth is described as seen, otherwise invisible; Continuous visible time border is visible time range; Wherein, T _FOVEqual the visual field size of ultraviolet sensors optical system for the visual field threshold value.

6, moon-tracking segment ultraviolet sensor earth and moon photography time predication method according to claim 1 is characterized in that: the best time is got described visible time range [t in the described step (3) ₁～t ₂] intermediate value, or [t ₁～t ₂] the angle  moment corresponding of time range minimum.

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