Pointing method of telescope system and telescope system

Abstract

A pointing method for a telescope system and a telescope system. Before observation, an error correction model is used to perform a preliminary correction on the pointing error of the telescope system. During the observation process, reference stars near the observation target are used to perform a secondary correction on the pointing error of the telescope system, thereby significantly improving the pointing accuracy of the telescope system.

Description

Technical Field

[0001] The present invention relates to the technical field of telescope systems, and in particular to a pointing method for a telescope system and a telescope system. Background Art

[0002] With the continuous development and progress of science and technology, the manufacturing accuracy and detection capabilities of optical telescope systems have been greatly improved. The angular resolution and extreme detection capabilities of the new generation of large-aperture telescopes have been effectively improved.

[0003] In the field of astronomical target observation and aerospace technology, using a telescope with a limited field of view to quickly and accurately point to a target is a key step in capturing the target and conducting measurements. Since the target orbit information and the ground telescope use different coordinate systems, and there is a certain error in the conversion of coordinate systems when the telescope system is installed and used in different environments, it is impossible to point and track the target with high precision.

[0004] Therefore, it is necessary to study a high-precision telescope system pointing method to achieve precise pointing of the telescope system to space observation targets in deep space target detection and communication missions. Summary of the invention

[0005] In view of the above problems, the present application provides a pointing method for a telescope system, which is described in detail below.

[0006] According to a first aspect, an embodiment provides a pointing method for a telescope system, comprising:

[0007] Selecting a reference star within a preset spatial range of the observation target, determining the coordinates of the reference star, and determining the relative deflection angle from the reference star to the observation target;

[0008] Correcting the pointing error of the telescope system using a pre-acquired error correction model function;

[0009] Observe the observation target, during the observation process:

[0010] Based on the coordinates of the reference star, controlling the telescope system to point to the reference star;

[0011] Adjusting the pointing data of the telescope system so that the reference star is located at the center of the field of view of the telescope system;

[0012] When the reference star is located at the center of the field of view of the telescope system, based on the relative deflection angle from the reference star to the observation target, the telescope system is controlled to change from pointing to the reference star to pointing to the observation target so as to observe the observation target.

[0013] In one embodiment, the pointing data includes an azimuth angle and an elevation angle of the telescope system.

[0014] In one embodiment, the error correction model function is determined in the following manner:

[0015] Select a preset number of first stars with known coordinates;

[0016] Determining theoretical pointing data of the telescope pointing to each first star based on the coordinates of the selected first star and the site coordinates of the telescope system;

[0017] controlling the telescope system to point to the first star, and determining actual pointing data of the telescope system pointing to each first star;

[0018] Based on the theoretical pointing data and the actual pointing data of a preset number of first stars, a preset fitting method is adopted to obtain the error correction model function.

[0019] In one embodiment, the preset fitting method includes: a spherical harmonic function model based on least squares fitting, or an axis system error model based on least squares fitting.

[0020] In one embodiment, adjusting the pointing data of the telescope system includes:

[0021] In response to the adjustment instruction input by the user, the pointing data of the telescope system is adjusted.

[0022] In one embodiment, determining the coordinates of the reference star comprises:

[0023] Obtaining the coordinates of the reference star in the equatorial coordinate system;

[0024] The coordinates of the reference star are converted from the equatorial coordinate system to the horizontal coordinate system to obtain the coordinates of the reference star in the horizontal coordinate system.

[0025] In one embodiment, determining the relative deflection angle from the reference star to the observation target comprises:

[0026] Obtaining the coordinates of the observed target in the geocentric inertial coordinate system;

[0027] Converting the coordinates of the observed target from the geocentric inertial coordinate system to the horizontal coordinate system to obtain the coordinates of the observed target in the horizontal coordinate system;

[0028] Based on the coordinates of the reference star in the horizontal coordinate system and the coordinates of the observation target in the horizontal coordinate system, a relative deflection angle from the reference star to the observation target is determined.

[0029] In one embodiment, the preset spatial range of the observation target is a range within which the angle between the line connecting the observation target to the telescope system and the line connecting the target star to the telescope system is within 10°.

[0030] According to a second aspect, in one embodiment, a telescope system is provided, comprising:

[0031] A telescope unit, used for collecting and detecting light energy reflected or emitted by the observation target;

[0032] The main control unit is used to execute the method described in any of the above embodiments to control the telescope unit to point to the observation target and observe the observation target.

[0033] According to the third aspect, an embodiment provides a computer-readable storage medium, characterized in that a computer program is stored on the medium, and the computer program can be executed by a processor to implement the method described in any of the above embodiments.

[0034] According to the pointing method of the telescope system and the telescope system of the above-mentioned embodiment, the pointing error of the telescope system is first corrected by using a pre-acquired error correction model function. During the observation of the observation target, the telescope system is controlled to point to the reference star based on the coordinates of the reference star within the preset spatial range of the observation target. Then, the pointing data of the telescope system is adjusted so that the reference star is located at the center of the field of view of the telescope system. When the reference star is located at the center of the field of view of the telescope system, the telescope system is controlled to change from pointing to the reference star to pointing to the observation target based on the relative deflection angle from the reference star to the observation target, so as to observe the observation target. Therefore, the present invention not only performs a preliminary correction on the pointing error of the telescope system by using the error correction model before observation, but also performs a secondary correction on the pointing error of the telescope system by using the reference stars near the observation target during the observation process, thereby significantly improving the pointing accuracy of the telescope system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flowchart of a pointing method for a telescope system according to an embodiment;

[0036] Figure 2 A structural block diagram of a telescope system according to an embodiment. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are for making the present application better understood. However, those skilled in the art can easily recognize that some features can be omitted in different situations, or can be replaced by other elements, materials, methods. In some cases, some operations related to the present application are not shown or described in the specification, this is to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0038] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0039] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0040] Please refer to Figure 1 , an embodiment of the present invention provides a pointing method for a telescope system, comprising the following steps:

[0041] Step 101: Select a reference star within the preset spatial range of the observation target, determine the coordinates of the reference star, and determine the relative deflection angle from the reference star to the observation target. The observation target may be a space target such as a spacecraft or a satellite. When observing the observation target, the preset spatial range of the observation target is the range within which the angle between the line connecting the observation target to the telescope system and the line connecting the target star to the telescope system is within 10°. Since the theoretical coordinates of the observation target are known, the site coordinates of the telescope system are also known, so the line connecting the observation target to the telescope system is determined. Based on this, a suitable target star is searched around the observation target as a reference star. The condition for a target star that can be used as a reference star is that the angle between the line connecting the target star to the telescope system and the line connecting the observation target to the telescope system is within 10°, and the coordinates of the target star are known.

[0042] The coordinates of the reference stars, the coordinates of the observation targets and the station coordinates of the telescope system mentioned above must all be in the same coordinate system in subsequent calculations. In astronomical observations, the coordinates of the stars are generally in the equatorial coordinate system, which takes the center of mass of the earth as the origin, the vernal equinox as the zero point, and uses right ascension and declination to represent the coordinates of celestial bodies. In deep space exploration missions, the coordinates of the observation targets are generally in the geocentric inertial coordinate system, which takes the center of mass of the earth as the origin, the X axis points to the vernal equinox (one of the intersections of the earth's equator and the ecliptic plane), the Z axis is perpendicular to the equator, and the Y axis, OZ axis and OX axis form a right-handed coordinate system. In the pointing of a large telescope system, the coordinates need to be transformed into a horizontal coordinate system with the telescope system as the origin. The horizontal coordinate system uses azimuth and pitch angle to represent the coordinates of the target. In this embodiment, the coordinates of the reference stars and the coordinates of the observation targets are both converted to the horizontal coordinate system, that is, the conversion from the equatorial coordinate system to the horizontal coordinate system and the conversion from the geocentric inertial coordinate system to the horizontal coordinate system are required.

[0043] In some embodiments, determining the coordinates of the reference star includes: first obtaining the coordinates of the reference star in the equatorial coordinate system; then converting the coordinates of the reference star from the equatorial coordinate system to the horizontal coordinate system to obtain the coordinates (azimuth and elevation) of the reference star in the horizontal coordinate system. To the horizontal coordinate system ( A , E ) can be obtained by the following expression:

[0044] ;

[0045] ;

[0046] ;

[0047] in, A represents the azimuth in the horizontal coordinate system, E represents the pitch angle in the horizontal coordinate system, represents the longitude in the equatorial coordinate system, Indicates the latitude in the equatorial coordinate system; are the site coordinates of the telescope system, is the longitude of the telescope system, is the latitude of the telescope system, represents the hour angle of the telescope system's site, S represents the hour angle of the vernal equinox, It indicates the vertical deviation between the gravity direction of the telescope system and the normal direction of the ground plane.

[0048] In some embodiments, determining the relative deflection angle from the reference star to the observation target includes: obtaining the coordinates of the observation target in the geocentric inertial coordinate system; converting the coordinates of the observation target from the geocentric inertial coordinate system to the horizontal coordinate system to obtain the coordinates of the observation target in the horizontal coordinate system; and determining the relative deflection angle from the reference star to the observation target based on the coordinates of the reference star in the horizontal coordinate system and the coordinates of the observation target in the horizontal coordinate system. Specifically, the coordinates of the telescope system in the geocentric inertial coordinate system can be obtained by the following expression:

[0049] ;

[0050] ;

[0051] ;

[0052] in, , , Indicates the coordinates of the telescope system on the X-axis, Y-axis, and Z-axis in the geocentric inertial coordinate system. are the coordinates of the telescope system's site, a is the longitude of the telescope system, is the latitude of the telescope system, t=S- a represents the hour angle of the telescope system's site, S represents the hour angle of the vernal equinox, r is the radius of the Earth.

[0053] In the geocentric inertial coordinate system, point from the telescope system to the observation target Vector for: .

[0054] Consider vertical deviation In this case, the normal direction of the ground plane of the horizontal coordinate system is for: ;in, It represents the angle between the gravity direction and the normal direction of the ground plane in the horizontal coordinate system. It represents the angle between the gravity direction and the normal direction of the ground plane in the spherical coordinate system.

[0055] Based on the above, according to and The azimuth and elevation angle of the observed target in the horizontal coordinate system with the telescope system as the origin can be calculated.

[0056] By obtaining the azimuth and elevation angles of the observed target in the horizontal coordinate system with the telescope system as the origin, and the azimuth and elevation angles of the reference star in the horizontal coordinate system with the telescope system as the origin, the relative deflection angle from the reference star to the observed target can be calculated.

[0057] Step 102: Correct the pointing error of the telescope system using the error correction model function acquired in advance.

[0058] The error correction model function can be constructed in the following ways:

[0059] The star calibration data set detectable by the telescope system is selected at different azimuths and elevations in the whole sky. The stars included in the star calibration data set are stars with known coordinates. Usually more than 18 stars are selected. The azimuth and elevation angles of the telescope system pointing to these stars in the star calibration data set are calculated based on the theoretical right ascension and declination, and are recorded as the theoretical pointing data set. ,in, is the theoretical azimuth, is the theoretical pitch angle.

[0060] Control the telescope system to point to the stars in the star calibration data set respectively. According to the miss distance of the stars in the field of view of the telescope system and the actual pointing of the telescope system, calculate the azimuth and elevation angle of the stars in the star calibration data set measured by the telescope system, and record it as the actual pointing data set. ,in, is the actual azimuth, is the actual pitch angle.

[0061] According to the theoretical pointing data of stars and the actual pointing data measured by the telescope system, the pointing error sequence of the azimuth axis and the pitch axis of the telescope system at different pointing positions can be obtained. and ,in and .

[0062] Based on the pointing error sequence and , using a spherical harmonic function model based on least squares fitting, or a shaft error model based on least squares fitting, etc., to fit the error correction model function , , preliminarily correct the pointing error of the telescope. For example, when using spherical harmonics for fitting, the expression of the error correction model function is as follows:

[0063] ;

[0064] ;

[0065] in,( a , e ) points to data, a is the azimuth, e is the pitch angle; and is the correction coefficient obtained by fitting.

[0066] Based on the error correction model function constructed as above, the pointing data of the telescope system is corrected before the telescope system observes. The pointing data of the telescope system are the pointing azimuth and pointing elevation of the telescope system. That is, the pointing azimuth and pointing elevation of the telescope system are corrected. For example, based on the calculated initial pointing azimuth, the initial pointing azimuth is corrected according to the error correction model function to obtain the corrected pointing azimuth. The pointing elevation is similarly corrected.

[0067] The above are the process steps before the telescope system observation. After the preliminary correction is completed, the observation of the observation target begins. During the observation process:

[0068] Step 103: Based on the coordinates of the reference star, control the telescope system to point to the reference star. As mentioned above, after calculating the azimuth and elevation angle of the reference star in the horizontal coordinate system with the telescope system as the origin, the theoretical pointing data of the telescope system pointing to the reference star can be obtained, and the telescope system is controlled to point to the reference star according to the theoretical pointing data.

[0069] Step 104: Adjust the pointing data of the telescope system so that the reference star is located at the center of the field of view of the telescope system. After the telescope system points to the reference star according to the theoretical pointing data in step 103, the telescope system itself may have a pointing error, so that at this time, according to the pointing of the theoretical pointing data, the reference star is not at the center of the field of view of the telescope system. Therefore, the pointing data of the telescope system needs to be adjusted in real time until the user observes that the reference star is located at the center of the field of view of the telescope system. In some embodiments, adjusting the pointing data of the telescope system includes: adjusting the pointing data of the telescope system in response to an adjustment instruction input by the user through an input device such as a keyboard or a mouse, for example, the current azimuth and / or elevation angle of the telescope system can be adjusted.

[0070] Step 105: When the reference star is located at the center of the field of view of the telescope system, based on the relative deflection angle from the reference star to the observation target, the telescope system is controlled to change from pointing to the reference star to pointing to the observation target to observe the observation target.

[0071] After the adjustment in step 104, the reference satellite is located at the center of the field of view of the telescope system. At this time, the pointing error of the telescope system has been corrected in real time. Then, based on the relative deflection angle from the reference star to the observation target calculated in step 101, the telescope system is controlled to change from pointing to the reference star to pointing to the observation target. That is, the pointing direction of the telescope system is controlled to deflect according to the relative deflection angle, so that the observation target can be pointed at with high precision.

[0072] In an embodiment of the present invention, a pre-constructed error correction model function is first used to perform a preliminary correction on the pointing error of the telescope system before observation. After the observation begins, the pointing error of the telescope system is corrected again using reference stars near the observation target to achieve high-precision pointing of the telescope to the target. Compared with the current pointing accuracy of several arc seconds, the pointing accuracy of the target can be improved to within 1 arc second, providing a highly reliable pointing method for observation of deep space spacecraft and establishment of communication links.

[0073] Based on the pointing method of the telescope system disclosed in the above embodiment, please refer to Figure 2 An embodiment of the present invention further provides a telescope system, which includes a telescope unit 201 and a main control unit 202.

[0074] In this embodiment, the telescope unit 201 and the main control unit 202 are the main components of the telescope system. Of course, the telescope system may also include some detection components and execution components connected to the main control unit 202, which will not be described in detail here.

[0075] The telescope unit 201 is an optical instrument used to observe distant objects such as aircraft or stars, so as to collect and detect the light energy reflected or emitted by the distant objects to be measured. In some embodiments, the telescope unit 201 generally adopts a horizontal axis system structure, and its pointing is driven by an azimuth axis parallel to the gravity direction and a pitch axis in the horizontal direction.

[0076] The main control unit 202 is connected to the telescope unit 201 and is used to execute the pointing method of the telescope system disclosed in the above embodiment.

[0077] Those skilled in the art will appreciate that all or part of the functions of the various methods in the above-mentioned embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to implement the above-mentioned functions. For example, the program is stored in the memory of the device, and when the program in the memory is executed by the processor, all or part of the above-mentioned functions can be implemented. In addition, when all or part of the functions in the above-mentioned embodiments are implemented by computer programs, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash disk or mobile hard disk, and can be downloaded or copied and saved in the memory of the local device, or the system of the local device is updated, and when the program in the memory is executed by the processor, all or part of the functions in the above-mentioned embodiments can be implemented.

[0078] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A pointing method for a telescope system, characterized in that: include: Selecting a reference star within a preset spatial range of the observation target, determining the coordinates of the reference star, and determining the relative deflection angle from the reference star to the observation target; Correcting the pointing error of the telescope system using a pre-acquired error correction model function; Observe the observation target, during the observation process: Based on the coordinates of the reference star, controlling the telescope system to point to the reference star; Adjusting the pointing data of the telescope system so that the reference star is located at the center of the field of view of the telescope system; When the reference star is located at the center of the field of view of the telescope system, based on the relative deflection angle from the reference star to the observation target, the telescope system is controlled to change from pointing to the reference star to pointing to the observation target so as to observe the observation target.

2. The method according to claim 1, characterized in that The pointing data includes an azimuth angle and an elevation angle of the telescope system.

3. The method according to claim 2, characterized in that The error correction model function is determined in the following manner: Select a preset number of first stars with known coordinates; Determining theoretical pointing data of the telescope system pointing to each first star based on the coordinates of the selected first star and the site coordinates of the telescope system; controlling the telescope system to point to the first star, and determining actual pointing data of the telescope system pointing to each first star; Based on the theoretical pointing data and the actual pointing data of a preset number of first stars, a preset fitting method is adopted to obtain the error correction model function.

4. The method according to claim 3, characterized in that The preset fitting method includes: a spherical harmonic function model based on least squares fitting, or an axis system error model based on least squares fitting.

5. The method according to claim 2, characterized in that The adjusting the pointing data of the telescope system comprises: In response to the adjustment instruction input by the user, the pointing data of the telescope system is adjusted.

6. The method according to claim 2, characterized in that Determining the coordinates of the reference star comprises: Obtaining the coordinates of the reference star in the equatorial coordinate system; The coordinates of the reference star are converted from the equatorial coordinate system to the horizontal coordinate system to obtain the coordinates of the reference star in the horizontal coordinate system.

7. The method according to claim 6, characterized in that Determining the relative deflection angle from the reference star to the observation target includes: Obtaining the coordinates of the observed target in the geocentric inertial coordinate system; Converting the coordinates of the observed target from the geocentric inertial coordinate system to the horizontal coordinate system to obtain the coordinates of the observed target in the horizontal coordinate system; Based on the coordinates of the reference star in the horizontal coordinate system and the coordinates of the observation target in the horizontal coordinate system, a relative deflection angle from the reference star to the observation target is determined.

8. The method according to any one of claims 1 to 7, characterized in that The preset spatial range of the observation target is a range within which the angle between the line connecting the observation target to the telescope system and the line connecting the target star to the telescope system is within 10°.

9. A telescope system, characterized in that: include: A telescope unit, used for collecting and detecting light energy reflected or emitted by the observation target; A main control unit is used to execute the method according to any one of claims 1 to 8, so as to control the telescope unit to point to the observation target and observe the observation target.

10. A computer-readable storage medium, characterized in that: A computer program is stored on the medium, and the computer program can be executed by a processor to implement the method according to any one of claims 1 to 8.

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