CN103487055A - Method for restoring target space distribution through satellite-inertia combination - Google Patents

Abstract

The invention relates to a method for restoring target space distribution through satellite-inertia combination and belongs to the technical field of celestial navigation. The method comprises the following steps of counting an posture transition matrix between a star sensor coordinate system and an equator inertia coordinate system by combining a real-time posture of a spacecraft with a mounting matrix of a star sensor; constructing normalized observing vectors according to information of an extracted target point of the star sensor; converting the matrix according to the posture of the star sensor under the equator inertia coordinate system, and counting a reference vector of the target point under the equator inertia coordinate system and a coordinate of a target under a two-dimensional coordinate system defined by right ascension and declination; repeatedly carrying out the steps, projecting the target points of multi-frame images to the two-dimensional coordinate system of a celestial sphere, and overlapping the target points together, so as to obtain a distribution map of the target points under the equator inertia coordinate system in the view field of the star sensor in a certain time period. According to the method, the problems that the workload for judging the type of the targets in the view field is large, and a result is not visually displayed when the post-analysis is carried out on the data of an in-orbit period of the star sensor are solved, and the basic data is simply and effectively provided for analyzing the result.

Description

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

Technical field

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

Background technology

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

Attitude determines and to be completed by attitude sensor, and as classical star/be used to star sensor and inertial navigation components in the integrated navigation mode, attitude sensor in good condition can complete well attitude and set the tasks.Yet regrettably, the residing space physics environment of spacecraft is also nonideal, utilizing the star sensor Correcting INS, in the process of compensation inertia device drift, the scenery occurred in its visual field is except effective observed object---fixed star, also comprise as planet, nebula, other spacecraft, space junk, the parasitic light that month forms and eruptive material of spacecraft self etc., these all belong to unexpected decoy.

Which kind of the target that star sensor photographs during in-orbit belongs to, and we can't real-time analysis, only can carry out analysis and distinguishing to data afterwards.The result that analysis obtains, can not only make us more understand space environment, also can make our spacecraft and star sensor work better, thereby more adapt to this space environment.Certainly, original star chart is the most directly perceived for analyzing these targets, still, due to the restriction of remote measurement bandwidth, can't transmit complete original star chart, only the impact point information exchange of star sensor extract real-time can be crossed under the remote measurement resource and is passed.

Now, how to utilize existing limited resource to be analyzed? it is extremely important that analytical approach just seems, usually, can, in conjunction with the real-time attitude data of spacecraft, adopt the methods such as simulation star chart, speeds match, 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 analysis result directly perceived, effective, and reduce the workload of analyzing, the invention provides a kind of method that star is used to combine the 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:

A kind of star is used to combine the method for restore target space distribution, and the method comprises the steps:

Step 1: in conjunction with spacecraft at red attitude of being used to coordinate system and star sensor at spaceborne installation matrix, calculate star sensor coordinate system and the red attitude transition matrix of being used between coordinate system;

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

Step 3: at the red attitude transition matrix of being used under coordinate system, calculate impact point at the red reference vector of being used under coordinate system according to star sensor, and calculate target at the red coordinate system of being used to the coordinate under the two-dimensional coordinate system of right ascension and declination definition;

Step 4: repeating step one, to step 3, projects to the celestial sphere two-dimensional coordinate system by the impact point of multiple image, is superimposed upon in piece image, obtains sometime in section star sensor visual field internal object point at the red distribution plan of being used under coordinate system.

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

The accompanying drawing explanation

Fig. 1 is that single frames star sensor data transformation is to the red process flow diagram of being used under coordinate system.

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

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

Embodiment

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

As shown in Figure 1, to the red process flow diagram of being used under coordinate system, specifically comprise step 1～step 3 for single frames star sensor data transformation.

Step 1:

Known spacecraft, at red attitude angle and the attitude transition matrix of being used under coordinate system, at spaceborne installation matrix, calculates star sensor coordinate system and the red attitude transition matrix of being used between coordinate system in conjunction with star sensor;

Suppose that star sensor is M at spaceborne installation matrix _ss, spacecraft is M at the red attitude transition matrix of being used under coordinate system _st, so, star sensor is M in red being used under coordinate system at the attitude transition matrix _xm=M _st* M _ss.

Step 2:

The normalized measurement vector of impact point information structuring that star sensor is extracted;

As shown in Figure 2, in figure, the O-uv plane is the star sensor photo coordinate system to the star sensor coordinate system, O _s-xyz is the star sensor image space coordinate system, OO _sfor the 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:

At the red attitude transition matrix of being used under coordinate system, calculate the target observation vector at the red reference vector of being used under coordinate system according to star sensor, and calculate target at the red coordinate system of being used to the coordinate under the two-dimensional coordinate system of (right ascension, declination) definition;

According to the star sensor obtained in step 1 at the red attitude transition matrix of being used under coordinate system, by the measurement vector S in the star sensor image space coordinate system _ibe transformed into red being used under coordinate system, obtain reference vector R _i.

$R_i={\left(\begin{array}{ccc}{x}_i& y_i& z_i\end{array}\right)}^T$

$={\left(\begin{array}{ccc}\cos {\mathrm{\α}}_i\cos {\mathrm{\δ}}_i& \sin {\mathrm{\α}}_i\cos {\mathrm{\δ}}_i& \sin {\mathrm{\δ}}_i\end{array}\right)}^T$

$=M_{\mathrm{xm}}^{-1}\·S_i$

$=M_{\mathrm{mx}}^{-1}\·\frac{1}{\sqrt{u_i^2+v_i^2+f^2}}{\left(\begin{array}{ccc}{u}_i& v_i& -f\end{array}\right)}^T$

This target at red (right ascension, declination) coordinate of being used under 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:

Repeating step one～step 3, project to the celestial sphere two-dimensional coordinate system by the multiframe impact point, is superimposed upon in piece image, obtains sometime section star sensor visual field internal object point at the red distribution plan of being used under coordinate system, as shown in Figure 3.In figure, the coordinate transverse axis is right ascension, and the coordinate longitudinal axis is declination, and unit is degree, and "+" is bright in the fixed star of 5.5Mv in star catalogue, and " * " reverts to the red coordinate of being used under coordinate system for the impact point in image, and " ◆ " means that the optical axis of star sensor points to.

Result of calculation shown in Fig. 3 can provide basic data for the target type that analysis enters in the star sensor visual field, and does preliminary judgement.If the impact point in image is fixed star, by the method revert to red be used to coordinate system after, should stably be arranged near a certain fixed star of star catalogue; And the target of other type, PRELIMINARY RESULTS can be by the image after stack, and evaluating objects point judges at the red movement locus of being used under coordinate system, 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 be done linear uniform motion; The target that those movement locus are consistent with star sensor optical axis movement locus, tentatively be judged as accompanying flying thing or the eruptive material of spacecraft.Further judgement will be analyzed together in conjunction with other data.

Claims (1)

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

Step 1: in conjunction with spacecraft at red attitude of being used to coordinate system and star sensor at spaceborne installation matrix, calculate star sensor coordinate system and the red attitude transition matrix of being used between coordinate system;

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

Step 3: at the red attitude transition matrix of being used under coordinate system, calculate impact point at the red reference vector of being used under coordinate system according to star sensor, and calculate target at the red coordinate system of being used to the coordinate under the two-dimensional coordinate system of right ascension and declination definition;

Step 4: repeating step one, to step 3, projects to the celestial sphere two-dimensional coordinate system by the impact point of multiple image, is superimposed upon in piece image, obtains sometime in section star sensor visual field internal object point at the red distribution plan of being used under coordinate system.

Images