CN103487055B - A kind of star is used to the method combining restore target space distribution - Google Patents

Abstract

The method that star is used to combine restore target space distribution belongs to a celestial navigation technical field, by conjunction with the real-time attitude of spacecraft and the installation matrix of star sensor, calculates the pose transformation matrix between star sensor coordinate system and red used coordinate system; To the normalized measurement vector of impact point information structuring that star sensor extracts; According to the pose transformation matrix of star sensor under red used coordinate system, calculate the reference vector of impact point under red used coordinate system, and calculate the coordinate of target under the two-dimensional coordinate system of red used coordinate system with right ascension and declination definition; Repeat above-mentioned steps, the impact point of multiple image is projected to celestial sphere two-dimensional coordinate system, is superimposed, obtain the distribution plan of star sensor visual field internal object point under red used coordinate system in section sometime.The invention solves ex-post analysis star sensor in-orbit period data time, differentiate that visual field internal object type of work amount is large, and result display not problem intuitively, in a straightforward manner effectively for interpretation of result provides basic data.

Description

A kind of star is used to the method combining restore target space distribution

Technical field

The invention belongs to celestial navigation technical field, be specifically related to a kind of method that star is used to combine restore target space distribution.

Background technology

Along with the development of science and technology, the mankind fight for the aggravation of resource, and the importance of spationautics significantly increases.Can predict, aerospace industry supports the mainstay industry of human sciences's research, daily life by becoming.In numerous links that spationautics has, spacecraft attitude determines it is wherein one of the most basic, most important task.

Attitude is determined to be completed by attitude sensor, and as the star sensor in the star/used integrated navigation mode of classics and inertial navigation components, attitude sensor in good condition can complete attitude determination task well.Unfortunately, space physics environment residing for spacecraft is also nonideal, utilizing star sensor Correcting INS, compensate in the process of inertia device drift, the scenery occurred in its visual field is except effective observed object---except fixed star, also comprise as planet, nebula, other spacecraft, space junk, the eruptive material etc. of the parasitic light that formed by the moon and spacecraft self, these all belong to unexpected decoy.

Which kind of the target that photographs belongs to star sensor period in-orbit, and we cannot real-time analysis, only can carry out analysis and distinguishing to data afterwards.Analyze the result obtained, us can not only be made more to understand space environment, our spacecraft and star sensor also can be made to work better, thus more adapt to this space environment.Certainly, original star chart is the most directly perceived for these targets of analysis, but due to the restriction of remote measurement bandwidth, cannot transmit complete original star chart, only can by the impact point information of star sensor extract real-time by passing under remote measurement resource.

Now, existing limited resource how is utilized to analyze? analytical approach just seems extremely important, usually, can, in conjunction with the real-time attitude data of spacecraft, adopt method such as simulation star chart, speeds match etc., but these methods are not directly perceived, and workload be large.

Summary of the invention

In order to solve problems of the prior art, obtain directly perceived, effective analysis result, and reduce the workload of analysis, the invention provides a kind of method that star is used to combine restore target space distribution, the method principle is simple, easy to use.

The technical scheme that technical solution problem of the present invention adopts is as follows:

Star is used to the method combining restore target space distribution, and the method comprises the steps:

Step one: in conjunction with spacecraft at the attitude of red used coordinate system and star sensor at spaceborne installation matrix, calculate the pose transformation matrix between star sensor coordinate system and red used coordinate system;

Step 2: the normalized measurement vector of impact point information structuring that star sensor is extracted;

Step 3: according to the pose transformation matrix of star sensor under red used coordinate system, calculates the reference vector of impact point under red used coordinate system, and calculates the coordinate of target under the two-dimensional coordinate system of red used coordinate system with right ascension and declination definition;

Step 4: repeat step one to step 3, the impact point of multiple image is projected to red used coordinate system, is superimposed upon in piece image, obtains the distribution plan of star sensor visual field internal object point under red used coordinate system in section sometime.

The invention has the beneficial effects as follows: the target data that multiframe star sensor extracts utilizes the mode of posture changing to revert to red used coordinate system by the present invention, and be converted to visual image, result intuitive display, method is simple, be easy to realize, workload is little, the target analyzed in aerial mission in star sensor visual field is had to the effect of very practical value and directiveness.

Accompanying drawing explanation

Fig. 1 is the process flow diagram under single frames star sensor data transforms to red used coordinate system.

Fig. 2 is star sensor photo coordinate system and image space coordinate system.

Fig. 3 is the superimposed image under the target in star sensor visual field reverts to red used coordinate system.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in further details.

As shown in Figure 1, for single frames star sensor data transforms to the process flow diagram under red used coordinate system, step one ~ step 3 is specifically comprised.

Step one:

The attitude angle of known spacecraft under red used coordinate system and pose transformation matrix, in conjunction with star sensor at spaceborne installation matrix, calculate the pose transformation matrix between star sensor coordinate system and red used coordinate system;

Suppose that star sensor is M at spaceborne installation matrix _ss, the pose transformation matrix of spacecraft under red used coordinate system is M _st, so, star sensor is M at pose transformation matrix under red used coordinate system _xm=M _st× M _ss.

Step 2:

To the normalized measurement vector of impact point information structuring that star sensor extracts;

As shown in Figure 2, in figure, O-uv plane is star sensor photo coordinate system to star sensor coordinate system, O _s-xyz is star sensor image space coordinate system, OO _sfor star sensor focal distance f, hypothetical target point S _icoordinate in star sensor image coordinates system is (u _i, v _i), impact point S _iafter the measurement vector normalization of star sensor image space coordinate system, be $S_i=\frac{1}{\sqrt{u_i^2+v_i^2+f^2}}{\left(\begin{array}{ccc}{u}_i& v_i& -f\end{array}\right)}^T.$

Step 3:

According to the pose transformation matrix of star sensor under red used coordinate system, calculate the reference vector of target observation vector under red used coordinate system, and calculate the coordinate under the two-dimensional coordinate system that target defines with (right ascension, declination) at red used coordinate system;

According to the pose transformation matrix of the star sensor obtained in step one under red used coordinate system, by the measurement vector S in star sensor image space coordinate system _iunder being transformed into red used coordinate system, obtain reference vector R _i.

$\begin{array}{c}{R}_i={\left(\begin{array}{ccc}{x}_i& y_i& z_i\end{array}\right)}^T\\ ={\left(\begin{array}{ccc}{\mathrm{cos\α}}_i{\mathrm{cos\δ}}_i& {\mathrm{sin\α}}_i{\mathrm{cos\δ}}_i& {\mathrm{sin\δ}}_i\end{array}\right)}^T\\ =M_{xm}^{-1}\·S_i\\ =M_{xm}^{-1}\·\frac{1}{\sqrt{u_i^2+v_i^2+f^2}}{\left(\begin{array}{ccc}{u}_i& v_i& -f\end{array}\right)}^T\end{array}$

(x _iy _iz _i) be the three-dimensional coordinate of fixed star under the line under rectangular coordinate system, (α _iδ _i) be the two-dimensional coordinate of fixed star under red used coordinate system.Then this target (right ascension, declination) coordinate under red used two-dimensional coordinate system is

$\left\{\begin{array}{c}{\mathrm{\α}}_i=\arctan 2(y_i/x_i)\\ {\mathrm{\δ}}_i=\arcsin \left(z_i\right)\end{array}\right..$

Step 4:

Repeat step one ~ step 3, multiframe impact point is projected to red used coordinate system, is superimposed upon in piece image, obtain the distribution plan of internal object point in section star sensor visual field under red used coordinate system sometime, as shown in Figure 3.In figure, abscissa line is right ascension, and the coordinate longitudinal axis is declination, and unit is degree, and "+", for bright in the fixed star of 5.5Mv in star catalogue, " * " is the coordinate under the impact point in image reverts to red used coordinate system, and " ◆ " represents that the optical axis of star sensor points to.

Result of calculation shown in Fig. 3 can provide basic data for analyzing the target type entered in star sensor visual field, and does preliminary judgement.If the impact point in image is fixed star, after reverting to red used coordinate system by the method, should stably be arranged near a certain fixed star of star catalogue; And the target of other type, PRELIMINARY RESULTS can by the image after superposition, and the movement locus of evaluating objects point under red used coordinate system judges, because the object of free flight in inertial space is not subject to or is subject to very little graviational interaction, by the law of inertia, object will do linear uniform motion; The target that those movement locus are consistent with star sensor optical axis movement locus, then be tentatively judged as accompanying flying thing or the eruptive material of spacecraft.Further judge, will analyze together in conjunction with other data.

Claims (1)

1. star is used to the method combining restore target space distribution, and it is characterized in that, the method comprises the steps:

Step one: in conjunction with spacecraft at the attitude of red used coordinate system and star sensor at spaceborne installation matrix, calculate the pose transformation matrix between star sensor coordinate system and red used coordinate system;

Step 2: the normalized measurement vector of impact point information structuring that star sensor is extracted;

Step 3: according to the pose transformation matrix of star sensor under red used coordinate system, calculates the reference vector of impact point under red used coordinate system, and calculates the coordinate of target under the two-dimensional coordinate system of red used coordinate system with right ascension and declination definition;

Step 4: repeat step one to step 3, the impact point of multiple image is projected to red used coordinate system, is superimposed upon in piece image, obtains the distribution plan of star sensor visual field internal object point under red used coordinate system in section sometime.