Full-automatic star calibration method for foundation photoelectric telescope

Abstract

The invention relates to the technical field of photoelectric detection, and provides a full-automatic star calibration method for a foundation photoelectric telescope, which comprises the following steps: constructing a fixed star list for calibration in a star map corresponding to the current moment; traversing fixed stars in the fixed star list, and based on the currently guided fixed star, judging whether the deviation between the current azimuth and pitching real-time position of the telescope and the position of the fixed star guided at the current moment is within a first threshold value; when the position of the mass center of the currently guided fixed star is within the first threshold value, acquiring the position of the mass center of the currently guided fixed star through an image acquisition system, and determining the miss distance of the currently guided fixed star based on the position of the mass center; the telescope control system calculates a miss distance variance based on the miss distance, and judges whether the miss distance variance is within a second threshold; and when the miss distance variance is within the second threshold value, storing the calibration data of the guided fixed star, and moving to the next fixed star for automatic calibration until all fixed stars in the fixed star list are traversed.

Description

Technical Field

[0001] The present application relates to the field of photoelectric detection technology, and in particular to a fully automatic star calibration method for a ground-based photoelectric telescope. Background Art

[0002] Ground-based photoelectric telescopes generally use manual star calibration to model and analyze the static pointing error of the telescope, so as to achieve real-time correction of the telescope pointing. Manual star calibration generally requires the operator to visually determine whether the image transmitted by the image acquisition software to the telescope control software meets the calibration conditions, and manually adjust it if it does not meet the calibration conditions. The overall operation process is cumbersome and requires human intervention. Faced with user requirements for unmanned, simplified, and automated observation tasks, manual calibration seems powerless.

[0003] In order to solve the above problems, the present application proposes a fully automatic star calibration method for a ground-based optoelectronic telescope, which realizes the star calibration process of a ground-based optoelectronic telescope by one click and automatically completes it. Summary of the invention

[0004] Some embodiments of the present application provide a fully automatic star calibration method for a ground-based photoelectric telescope, comprising:

[0005] In the star map corresponding to the current moment, a list of stars for calibration is constructed;

[0006] Traversing the stars in the star list, based on the currently guided star, determining whether the deviation between the current azimuth and elevation real-time position of the telescope and the position of the guided star at the current moment is within a first threshold;

[0007] When it is within the first threshold, the center of mass position of the currently guided star is acquired through an image acquisition system, and the miss distance of the currently guided star is determined based on the center of mass position;

[0008] The telescope control system calculates the miss amount variance based on the miss amount, and determines whether the miss amount variance is within a second threshold;

[0009] When the miss distance variance is within the second threshold, the calibration data of the guided star is saved, and the next star is moved to perform automatic calibration until all the stars in the star list are traversed.

[0010] In some embodiments, it also includes:

[0011] When it is not within the first threshold, the current azimuth and elevation real-time position of the telescope is automatically adjusted within a preset time range until the deviation of the star position guided by it at the current moment is within the first threshold.

[0012] In some embodiments, it also includes:

[0013] When it is not within the second threshold, the current azimuth and elevation real-time position of the telescope is automatically adjusted within the preset time range until the deviation of the star position guided by it at the current moment is within the first threshold and the miss amount variance is within the second threshold.

[0014] In some embodiments, the preset time refers to the sum of the maximum turning time of the telescope and the waiting time for collecting the off-target amount.

[0015] In some embodiments, the maximum turning time of the telescope refers to the time required for the telescope to turn from 0 degrees to 360 degrees; the waiting time for collecting the off-target amount is 15-30 seconds.

[0016] In some embodiments, determining the miss distance of the currently guided star based on the center of mass position includes:

[0017] Calculate the deviation distance of the centroid position from the crosshair center in pixels;

[0018] The deviation distance is multiplied by the field of view corresponding to a single pixel in arc seconds to obtain the miss distance of the currently guided star.

[0019] In some embodiments, the off-target amount variance satisfies the following condition: σ≥σ tele +a image p

[0020] Among them, σ is the variance of the miss amount, σ tele is the telescope servo tracking accuracy; a image is the star centroid extraction accuracy in pixels; p is the field of view corresponding to a single pixel of the camera, in arc seconds per pixel.

[0021] In some embodiments, constructing a star list for calibration in the star map corresponding to the current moment includes:

[0022] In the star map corresponding to the current moment, 30 to 70 stars with azimuths of 0 to 360 degrees, elevations of 20 to 85 degrees, and magnitudes of 4 to 5 are randomly selected at uniform intervals to construct a star list for calibration.

[0023] In some embodiments, it also includes:

[0024] A calibration file is established to store the calibration data, and the calibration data is used to solve the static pointing error correction model of the telescope.

[0025] In some embodiments, it also includes:

[0026] Based on the calibration data of all the stars in the star list, the static pointing error of the telescope is corrected through a model solving module.

[0027] Compared with the related art, the above solution of the embodiment of the present application has at least the following beneficial effects:

[0028] This application proposes a fully automatic star calibration method for ground-based optoelectronic telescopes, which improves the previous manual star calibration method by an automated process. Through calibration steps such as whether the telescope is in place, whether the variance of the off-target amount meets the threshold conditions, and whether the loop judges the timeout, the star calibration process is automatically completed.

[0029] This application can effectively solve the problem of human intervention required in the traditional manual star calibration process, and provides necessary technical support for the unmanned, simplified and automated observation of ground-based photoelectric telescopes. It can be applied to all types of ground-based photoelectric telescopes, such as equatorial and horizontal types. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0031] Figure 1 A schematic diagram of a flow chart of a fully automatic star calibration method for a ground-based optoelectronic telescope provided in some embodiments of the present application;

[0032] Figure 2 A flow chart of a method for fully automatic star calibration of a ground-based optoelectronic telescope provided in some embodiments of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0034] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0035] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] It should be understood that although the terms first, second, third, etc. may be used to describe in the embodiments of the present application, these should not be limited to these terms. These terms are only used to distinguish. For example, without departing from the scope of the embodiments of the present application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0037] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a product or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such product or device. In the absence of more restrictions, the elements defined by the sentence "comprises a" do not exclude the presence of other identical elements in the product or device including the elements.

[0038] When ground-based photoelectric telescopes track and measure the observed targets in real time, due to the existence of their own system errors and the changes in the azimuth and elevation angles of the observations, the telescope pointing needs to be corrected in real time. Generally, the static pointing error correction model of the telescope is established by calibrating multiple stars in the entire sky. According to the static pointing error correction model of the telescope, the azimuth and elevation angles of the current telescope are corrected in real time during tracking to reduce the pointing error.

[0039] In order to establish a static pointing error correction model for ground-based photoelectric telescopes, the traditional method is to uniformly collect star images of the entire sky, extract the miss-target amount, and then analyze the static pointing error correction model. Most of them are based on various models and methods to calculate the static pointing error correction model of ground-based photoelectric telescopes. However, when obtaining the correction model, it generally relies on manual intervention, often requiring manual star selection, or manual determination of whether the star miss-target amount meets the requirements, which does not meet the requirements of unmanned, simplified, and automated telescope operation.

[0040] To this end, the present invention provides a fully automatic star calibration method for a ground-based optoelectronic telescope, comprising: constructing a star list for calibration in a star map corresponding to the current moment; traversing the stars in the star list, and judging whether the deviation between the current azimuth and elevation real-time positions of the telescope and the positions of the stars guided at the current moment is within a first threshold value based on the currently guided stars; when within the first threshold value, acquiring the center of mass position of the currently guided star through an image acquisition system, and determining the miss amount of the currently guided star based on the center of mass position; the telescope control system calculates the miss amount variance based on the miss amount, and judges whether the miss amount variance is within a second threshold value; when the miss amount variance is within the second threshold value, saving the calibration data of the guided star, and moving to the next star for automatic calibration until all the stars in the star list are traversed.

[0041] This application proposes a fully automatic star calibration method for ground-based optoelectronic telescopes, which improves the previous manual star calibration method by an automated process. Through calibration steps such as whether the telescope is in place, whether the variance of the off-target amount meets the threshold conditions, and whether the loop judges the timeout, the star calibration process is automatically completed.

[0042] The present application is described in detail below with reference to the accompanying drawings.

[0043] like Figure 1 As shown, some embodiments of the present application provide a method for fully automatic star calibration of a ground-based photoelectric telescope. The fully automatic star calibration process of a ground-based photoelectric telescope is completed by the collaboration of two software systems, namely the telescope control software system and the image processing software. Among them, the telescope control software is responsible for the control of the telescope and the execution of the fully automatic star calibration; the image processing software system is responsible for the extraction of the off-target amount of the star image. Specifically, the method includes the following method steps:

[0044] Step S102: constructing a star list for calibration in the star map corresponding to the current moment;

[0045] Step S104: traversing the stars in the star list, and judging whether the deviation between the current azimuth and elevation real-time position of the telescope and the position of the star guided at the current moment is within a first threshold based on the currently guided star;

[0046] Step S106: when it is within the first threshold, the center of mass position of the currently guided star is acquired by an image acquisition system, and the miss distance of the currently guided star is determined based on the center of mass position;

[0047] Step S108: the telescope control system calculates the miss amount variance based on the miss amount, and determines whether the miss amount variance is within a second threshold;

[0048] Step S110: When the miss distance variance is within the second threshold, the calibration data of the guided star is saved, and the next star is moved to perform automatic calibration until all the stars in the star list are traversed.

[0049] Before step S102, it is necessary to click the automatic calibration button in the telescope control software system, and the telescope control software system starts the fully automatic star calibration program. Optionally, a calibration file is established in the telescope control software system. The calibration data in the subsequent execution of the calibration program is stored in this file, and the calibration data is used for the subsequent calculation of the static pointing error correction model of the telescope.

[0050] In step S102, in the star map corresponding to the current moment, constructing a star list for calibration includes: randomly selecting 30 to 70 stars at azimuths of 0 to 360 degrees, elevations of 20 to 85 degrees, and magnitudes of 4 to 5 at uniform intervals in the star map corresponding to the current moment to construct a star list for calibration. The specific number of calibration stars can be adjusted dynamically, and there is no strict limit on this.

[0051] After the star list is constructed, any star is selected as the currently guided star, and the stars in the star list are traversed in this way. The telescope control software system automatically guides the telescope to point to the next star in turn, and the pointing position of the star is calculated in real time to determine whether the deviation of the current azimuth and pitch real-time position of the telescope from the position of the star guided at the current moment is within the first threshold. The first threshold can usually be pre-set in the telescope control software system according to the accuracy requirements. The first threshold includes a preset azimuth and pitch angle range, and the specific value is not limited. For example, the azimuth angle is within plus or minus 2 arc seconds, and the pitch angle is within plus or minus 2 arc seconds. When the deviation of the current azimuth and pitch real-time position of the telescope from the position of the star guided at the current moment is within the first threshold, the center of mass position of the currently guided star is collected by the image acquisition system, and the miss amount of the currently guided star is determined based on the center of mass position.

[0052] When the telescope is aimed at a star, the offset of the azimuth and elevation angles at the current moment relative to the center of the crosshairs is the miss distance. The miss distance satisfies the following relationship:

[0053] A=A e +ΔA

[0054] E=E e +ΔE

[0055] Among them, A and E are the azimuth and elevation angles of the star, respectively. e and E e are the azimuth and elevation angles output by the encoder respectively, and ΔA and ΔE are the miss values ​​of azimuth and pitch respectively.

[0056] In some embodiments, determining the miss amount of the currently guided star based on the center of mass position includes: calculating the deviation distance of the center of mass position from the center of the crosshairs in pixels; multiplying the deviation distance by the field of view corresponding to a single pixel in arc seconds to obtain the miss amount of the currently guided star.

[0057] In some embodiments, when the deviation between the current azimuth and elevation real-time position of the telescope and the position of the star guided at the current moment is not within a first threshold, the current azimuth and elevation real-time position of the telescope are automatically adjusted within a preset time range until the deviation of the position of the star guided at the current moment is within the first threshold.

[0058] Furthermore, when the deviation between the current azimuth and elevation real-time positions of the telescope and the positions of the stars guided at the current moment is within a first threshold, the telescope control system calculates the miss amount variance based on the miss amount, and determines whether the miss amount variance is within a second threshold.

[0059] In some embodiments, the off-target amount variance satisfies the following second threshold condition:

[0060] σ≥σ tele +a image p;

[0061] Among them, σ is the variance of the miss amount, σ tele is the telescope servo tracking accuracy; a image is the star centroid extraction accuracy in pixels; p is the field of view corresponding to a single pixel of the camera, in arc seconds per pixel.

[0062] In some embodiments, when the miss variance is not within the second threshold, the current azimuth and elevation real-time position of the telescope are automatically adjusted within the preset time range until the deviation of the star position guided by it at the current moment is within the first threshold and the miss variance is within the second threshold.

[0063] The preset time refers to the sum of the maximum turning time of the telescope and the waiting time for the miss amount collection. In some embodiments, the maximum turning time of the telescope refers to the time required for the telescope to turn from 0 degrees to 360 degrees; the waiting time for the miss amount collection is 15-30 seconds, for example, 20 seconds. The calibration of a single star needs to determine whether it has timed out, otherwise the calibration time will not end or last too long.

[0064] When the miss amount variance is within the second threshold, the calibration data of the guided star is saved, and the next star is moved to automatic calibration until all the stars in the star list are traversed. The telescope software system automatically stores the miss amount data (including timestamp) in the calibration file for subsequent use.

[0065] In some embodiments, it also includes: based on the calibration data of all stars in the star list, the static pointing error of the telescope is corrected by a model solving module. Specifically, a single difference method or a spherical harmonic difference method can be selected to solve the calibration data to obtain a static pointing error correction model for the telescope. The specific algorithm is not described here in detail, and can be implemented by referring to related technologies.

[0066] According to the above process, the horizontal ground-based photoelectric telescope was tested. The experiment shows that this method can realize the automatic execution of star calibration of ground-based photoelectric telescope. At the same time, this method has also been applied and verified in actual engineering projects with good results.

[0067] This application proposes a fully automatic star calibration method for ground-based optoelectronic telescopes, which improves the previous manual star calibration method by an automated process. Through calibration steps such as whether the telescope is in place, whether the variance of the off-target amount meets the threshold conditions, and whether the loop judges the timeout, the star calibration process is automatically completed.

[0068] This application can effectively solve the problem of human intervention required in the traditional manual star calibration process, and provides necessary technical support for the unmanned, simplified and automated observation of ground-based photoelectric telescopes. It can be applied to all types of ground-based photoelectric telescopes, such as equatorial and horizontal types.

[0069] Finally, it should be noted that: each embodiment in this specification is described by way of example, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0070] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fully automatic star calibration method for a ground-based photoelectric telescope, characterized in that ,include: In the star map corresponding to the current moment, a list of stars for calibration is constructed; Traversing the stars in the star list, based on the currently guided star, determining whether the deviation between the current azimuth and elevation real-time position of the telescope and the position of the guided star at the current moment is within a first threshold; When it is within the first threshold, the center of mass position of the currently guided star is acquired through an image acquisition system, and the miss distance of the currently guided star is determined based on the center of mass position; The telescope control system calculates the miss amount variance based on the miss amount, and determines whether the miss amount variance is within a second threshold; When the miss distance variance is within the second threshold, the calibration data of the guided star is saved, and the next star is moved to perform automatic calibration until all the stars in the star list are traversed.

2. The method according to claim 1, characterized in that , also includes: When it is not within the first threshold, the current azimuth and elevation real-time position of the telescope is automatically adjusted within a preset time range until the deviation of the star position guided by it at the current moment is within the first threshold.

3. The method according to claim 2, characterized in that , also includes: When it is not within the second threshold, the current azimuth and elevation real-time position of the telescope is automatically adjusted within the preset time range until the deviation of the star position guided by it at the current moment is within the first threshold and the miss amount variance is within the second threshold.

4. The method according to claim 3, characterized in that ,The preset time refers to the sum of the maximum turning time of the telescope and the missing amount collection waiting time.

5. The method according to claim 4, characterized in that ,The maximum turning time of the telescope refers to the time required for the telescope to turn from 0 degrees to 360 degrees; the waiting time for collecting the off-target amount is 15-30 seconds.

6. The method according to claim 1, characterized in that The step of determining the miss distance of the currently guided star based on the center of mass position comprises: Calculate the deviation distance of the centroid position from the crosshair center in pixels; The deviation distance is multiplied by the field of view corresponding to a single pixel in arc seconds to obtain the miss distance of the currently guided star.

7. The method according to claim 1, characterized in that , the off-target amount variance satisfies the following conditions: σ≥σ tele +a image p Among them, σ is the variance of the miss amount, σ tele is the telescope servo tracking accuracy; a image is the star centroid extraction accuracy in pixels; p is the field of view corresponding to a single pixel of the camera, in arc seconds per pixel.

8. The method according to claim 1, characterized in that , the star list for calibration is constructed in the star map corresponding to the current moment, including: In the star map corresponding to the current moment, 30 to 70 stars with azimuths of 0 to 360 degrees, elevations of 20 to 85 degrees, and magnitudes of 4 to 5 are randomly selected at uniform intervals to construct a star list for calibration.

9. The method according to claim 1, characterized in that , also includes: A calibration file is established to store the calibration data, and the calibration data is used to solve the static pointing error correction model of the telescope.

10. The method according to claim 1, characterized in that , also includes: Based on the calibration data of all the stars in the star list, the static pointing error of the telescope is corrected through a model solving module.

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