A Closed-Loop Tracking and Guidance Method and Guidance System for a Telescope

Abstract

The present invention relates to the technical field of telescope control, and specifically provides a closed-loop tracking and guiding method and a guiding system for a telescope. The trigger frequency is set to an integer multiple of the frequency for receiving the actual guiding direction, and it is confirmed whether to trigger the telescope guiding according to this multiple. When performing telescope guiding, according to the target miss distance and the encoder pointing fitting trajectory formula, the target reference guiding direction is calculated, and the target reference guiding direction and the target miss distance are superimposed to obtain the actual guiding direction for guiding the telescope to rotate, so as to guide the telescope to rotate and track the target. This method does not need to consider the time alignment problem of each module, effectively reduces the jitter degree of the target in the field of view, and improves the tracking accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of telescope control, and particularly provides a closed-loop tracking and guiding method and a guiding system for a telescope. Background Art

[0002] Closed-loop tracking is one of the important component functions of an optoelectronic telescope. When a target enters the imaging field of view of the telescope, the telescope image processing module starts to perform real-time target extraction on each frame of the image. The image processing module calculates the pixel coordinates of the centroid of the target area in the image, and calculates the target miss distance according to the image optical parameters (angular resolution in the azimuth and elevation directions). The miss distance represents the angular offset of the target relative to the center of the telescope image field of view in the azimuth and elevation directions. A guiding instruction for the servo control module is generated based on the target miss distance, and finally the closed-loop tracking function of the telescope for the target is realized. The closed-loop tracking function plays an important role when the telescope observes a target with an unknown orbit or when the known orbit error of the observed target is relatively large.

[0003] A complete telescope system with the function of target closed-loop tracking generally includes five parts: a timing module, a servo control module, a camera, an image processing module, and a telescope control module. The existing mature telescope closed-loop tracking technology requires that the trigger period of the timing module, the camera shooting period, and the period for the servo control module to receive guiding instructions and encoder pointing feedback be strictly aligned. If the above-mentioned strict timing alignment cannot be achieved, it will cause a certain deviation between the telescope guiding pointing generated by the telescope control module and the actual pointing of the target, and finally it will be manifested as severe jitter of the target within the observed image range, and the faster the target moves, the more severe the jitter. For a telescope with a small observation field of view, the target may jitter outside the observation field of view, resulting in the failure of closed-loop tracking.

[0004] In the prior art, the image processing module processes the target image in real time, superimposes the calculated azimuth and elevation miss distances on the azimuth and elevation encoder pointings of the telescope at the central moment of the image, and finally obtains the target pointing at that moment. The telescope control module sends the target pointing at that moment to the servo control module, and the servo control module smoothly guides the telescope to the corresponding pointing in the next control cycle. This mode is applicable to the current relatively mature optoelectronic telescope system and depends on the perfect overall scheme design of the telescope. The timing module, the servo control module, the camera, the image processing module, and the telescope control module need to have a perfect cooperation mechanism and strict time alignment with each other to achieve. And this highly complex cooperation mechanism and time alignment method conflict with the modular design of the product to a certain extent, which will increase the design cost of the telescope, and also requires the R & D team to have high professionalism and rich experience. Currently, some models of telescope products do not support the existing mature closed-loop tracking solutions for the selection of the servo control module and the timing module. Summary of the Invention

[0005] To solve the above problems, the present invention provides a closed-loop tracking and guiding method and a guiding system for a telescope. Through a trajectory fitting formula, the dependence of the closed-loop function of the telescope on the time alignment of each module is effectively reduced, and the jitter degree of the target in the telescope field of view in this case is reduced.

[0006] The closed-loop tracking and guiding method for the telescope provided by the present invention includes:

[0007] S1: Preset a trigger frequency , and provide time information according to the trigger frequency, where represents the serial number of the time information;

[0008] S2: Preset the receiving frequency of the actual guiding direction. The actual guiding direction is the data for guiding the telescope to track the target;

[0008] S3: Set

[0009] , and judge whether to perform telescope guiding for this trigger: If

[0010] the remainder of is 0, then perform telescope guiding and execute the next step; If

[0011] the remainder of is not 0, then do not perform telescope guiding and the process ends; S4: Preset a collection frequency

[0012] , and collect the target image and calculate the target off-target amount corresponding to the target image according to the collection frequency, where represents the azimuth target off-target amount, represents the pitch target off-target amount;

[0013] S5: Obtain the telescope encoder pointing closest to the current time information , where represent the azimuth encoder pointing and the pitch encoder pointing respectively;

[0014] S6: Perform target trajectory fitting and calculate the target reference guiding direction :

[0015] Q1: Calculate the approximate target pointing ; obtain the target pointing information ; add the target pointing information to the head of the information queue , where the information queue is the target pointing information A collection arranged in chronological order of time information;

[0016] Q2: Set the quantity threshold , and determine whether the quantity of the target pointing information in the information queue is less than or equal to the quantity threshold :

[0017] If so, keep the information queue unchanged;

[0018] If not, delete the target pointing information at the end of the information queue to obtain a new information queue ; ;

[0019] Q3: Obtain the trajectory fitting formula based on the information queue :

[0020] ;

[0021] Among them, represents the azimuth value or pitch value of the target reference guiding direction , , and represent the coefficients of the azimuth value trajectory fitting formula of the target reference guiding direction or the coefficients of the pitch value trajectory fitting formula of the target reference guiding direction ;

[0022] Q4: Solve the coefficients , and by the least squares method to obtain the target reference guiding direction ;

[0023] S7: Superimpose the target reference guiding direction and the target miss distance to solve the actual guiding direction , and guide the telescope through the actual guiding direction .

[0024] Preferably, the trigger frequency is an integer multiple of the guiding frequency .

[0025] Preferably, the trigger frequency is an integer multiple of the acquisition frequency .

[0026] Preferably, the trigger frequency is set to 100 Hz.

[0027] Preferably, the quantity threshold is set to 20.

[0028] A closed-loop tracking and guiding system for a telescope, guiding the telescope based on the closed-loop tracking and guiding method of the telescope, comprising:

[0029] a timing module, a servo control module, a camera, a telescope control module and an image processing module;

[0030] The timing module provides time information;

[0031] The camera acquires a target image and sends the target image to the image processing module;

[0032] The image processing module calculates the target miss distance in the target image according to the target image, and sends the target miss distance to the telescope control module;

[0033] The servo control module receives the actual guiding direction to guide the telescope to track the target, and sends the encoder direction to the telescope control module;

[0034] The telescope control module calculates the actual guiding direction according to the encoder direction, the target miss distance and the time information and sends it to the servo control module.

[0035] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0036] For the type of telescope involved in the present invention, using the existing method to perform closed-loop tracking on the target will cause severe jitter of the target within the image field of view.

[0037] The present invention effectively reduces the dependence of the telescope closed-loop function on the time alignment of each module through trajectory formula fitting, and can greatly reduce the jitter amplitude and frequency of the target during the closed-loop tracking of this type of telescope, so that the target can be kept as close as possible to the center of the observation field of view.

[0038] Moreover, in the control system of the present invention, the telescope control module and the image processing module can be in one software, or in different softwares, and can be in one terminal, or in different terminals, with higher flexibility and more convenient to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a flowchart of the closed-loop tracking and guiding method for a telescope provided by an embodiment of the present invention;

[0040] Figure 2 is a flowchart for generating a trajectory fitting formula provided by an embodiment of the present invention;

[0041] Figure 3It is a structural diagram of a closed-loop tracking and guiding system of a telescope provided according to an embodiment of the present invention. Detailed implementation manners

[0042] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments are labeled with related similar element numbers. In the following embodiments, many detailed descriptions are provided to enable a better understanding of the present invention. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present invention are not shown or described in the specification, which is to avoid the core part of the present invention being overwhelmed by excessive descriptions. 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 based on the description in the specification and general technical knowledge in the art.

[0043] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various embodiments. At the same time, the steps or actions in the method description can also be adjusted in the order that can be obviously understood by those skilled in the art. Therefore, the various orders in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary orders, unless it is indicated that a certain order must be followed.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0045] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0046] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0047] like Figure 1 As shown, an embodiment of the present invention provides a closed-loop tracking and guiding method for a telescope, comprising:

[0048] Figure 1 This is the main process of telescope closed-loop tracking, which is executed by a single trigger of the timing module. The overall process of actual closed-loop tracking is performed by the timing module according to its trigger frequency. A trigger signal and corresponding time information are sent to the telescope control module, and the telescope control module continuously executes this process after receiving the trigger signal. The embodiment of the present invention only describes a single trigger process, which is as follows:

[0049] S1: Set the trigger frequency , the timing module of the telescope guidance system follows the trigger frequency Provide time information ,in, Indicates the serial number of the time information. Here the time information That is, as a trigger signal, it may trigger the boot process.

[0050] S2: In the embodiment of the present invention, the guidance data that finally guides the telescope to track the target is called the actual guidance direction, and the receiving frequency of the actual guidance direction is preset. , trigger frequency is the guide frequency An integer multiple of .

[0051] S3: Because the system requires trigger frequency is the receiving frequency Therefore, it is not necessarily the case that every trigger signal will cause the telescope control module to guide the telescope. Therefore, it is necessary to judge whether a certain trigger signal triggers the telescope guidance.

[0052] The embodiment of the present invention is used express and The ratio of , the sequence number of the trigger signal It can indicate the number of times of triggering and determine whether to perform telescope guidance for this triggering:

[0053] Due to the trigger frequency being an integer multiple of the reception frequency In the embodiments of the present invention uses to represent this multiple relationship, that is, the trigger frequency is times of the reception frequency , where is an integer. Then, every triggers, a telescope guidance is performed once.

[0054] If has a remainder of 0 when divided by, then this triggering performs telescope guidance and proceeds to the next step;

[0055] If has a non - zero remainder when divided by, then no telescope guidance is performed and the process ends.

[0056] S4: Preset the acquisition frequency , which is used to represent the frequency at which the camera acquires the target image. Acquire the target image according to the acquisition frequency . After confirming the telescope guidance, acquire the target image based on this trigger signal and calculate the target miss distance corresponding to the target image. In the embodiments of the present invention, is used to represent the target miss distance, that is , where represents the azimuth target miss distance, represents the elevation target miss distance. Among them, the trigger frequency is an integer multiple of the acquisition frequency .

[0057] S5: Obtain the telescope encoder pointing nearest to the current time information, where respectively represent the azimuth encoder pointing and the elevation encoder pointing.

[0058] S6: After obtaining the target miss distance and the encoder pointing , perform target trajectory fitting, and then calculate the target reference guidance pointing .

[0059] As Figure 2 shown, the trajectory formula fitting method is as follows:

[0060] Q1: Trigger the trajectory formula fitting process through the image processing module. When the image processing module sends the target miss distance to the telescope control module connected to the image processing module, the trajectory formula fitting process is triggered.

[0061] In the embodiment of the present invention, is used to represent the time information provided by the timing module, is used to represent the serial number of the time information, is used to represent the previous time information of the time information with the serial number . When the obtained time information is , the encoder corresponding thereto points to , where respectively represent the azimuth encoder pointing and the pitch encoder pointing.

[0062] In the embodiment of the present invention, is used to represent the target approximate pointing corresponding to the time information, , where respectively represent the azimuth value and the pitch value of the target approximate pointing, and calculate the target approximate pointing :

[0063] ;

[0064] Form an information group by combining the calculated target approximate pointing with the time information corresponding to the target approximate pointing. In the embodiment of the present invention, this information group is called target pointing information , that is .

[0065] Arrange all the target pointing information in a queue according to the sequence of time information , and each time the obtained target pointing information is added to the head of the information queue .

[0066] Q2: Set a quantity threshold . Each time a target pointing information is added to the information queue , judge the quantity of the target pointing information in the information queue. If the quantity of the target pointing information is greater than the quantity threshold , delete the target pointing information at the end of the information queue . If the quantity of the target pointing information is less than or equal to the quantity threshold , do not delete the target pointing information . This operation controls the quantity of the target pointing information in the information queue within a certain range. It should be noted that the value of the quantity threshold is related to the aforementioned frequency , , and There is a negative correlation, that is, , and the smaller the value of, the larger the quantity threshold needs to be set. The larger the value of, the more effectively the target jitter can be reduced during the target closed-loop tracking process. In this embodiment, , , , , the target jitter can be effectively reduced.

[0067] Set the information queue is denoted as , set to represent any target pointing information in the information queue , where , represents the serial number of the information queue from the target pointing information , , can be understood as a serial number with a sequence. Then , when , it means that the corresponding target pointing information is the first in the information queue . When , it means that the corresponding target pointing information is the last in the information queue . When a new target pointing information is calculated and obtained, it is added to the first place of the information queue , and the target pointing information is marked as . All the original target pointing information in the information queue has its serial number automatically increased by 1. At this time, if appears, it means that there is a target pointing information exceeding the quantity threshold . is deleted from the information queue to ensure that the upper limit of the number of target pointing information in the information queue is .

[0068] Q3: After obtaining the information queue , apply all the target pointing information in the information queue to generate a trajectory fitting formula and further obtain the target reference guiding direction , the generation method is as follows:

[0069] Since , where respectively represent the azimuth value and pitch value pointed by the target reference guidance. For the embodiments of the present invention, and have the same solution method. Therefore, when performing trajectory fitting to obtain the target reference guidance, the solution method is only described once, and is used to represent or . Let the expression of the trajectory fitting formula be , where , , all represent the coefficients of the trajectory fitting formula. It should be noted that for the solution of and , the coefficients of their trajectory fitting formulas are not the same, but the solution methods are the same. Therefore, in the embodiments of the present invention, , , are used for representation, and the coefficients are not distinguished, that is , and represent the coefficients of the azimuth value trajectory fitting formula of the target reference guidance or the coefficients of the pitch value trajectory fitting formula of the target reference guidance . Fitting the trajectory fitting formula in the above form based on multiple coordinates is a prior art.

[0070] Q4: To solve the coefficients of the expression of the trajectory fitting formula, the embodiments of the present invention use the least squares method to solve the coefficients. The above method for solving the coefficients is a mature prior art and will not be elaborated here.

[0071] The trajectory fitting formula is obtained by fitting using historical target pointing information. The target reference guidance calculated by this formula has hysteresis. If the telescope control module uses the target reference guidance to guide the telescope, it will cause a certain offset of the target from the center of the field of view. The offset amplitude is related to the change rate of the rotational acceleration of the telescope in the azimuth and pitch directions. Therefore, adding the target miss amount to the target reference guidance as the telescope guidance can make the target approach the center of the field of view.

[0072] S7: Through the above process, the target reference guidance can be solved, and the target miss amount sent by the image processing module that is closest to the target reference guidance is obtained. The target reference guidance is added to the closest target miss amount to obtain the actual guidance , namely . The telescope control module sends the actual guiding pointing to the servo control module, and applies the actual guiding pointing to guide the telescope, completing the guiding of the telescope in this cycle.

[0073] It should be noted that the closed-loop tracking main process and the trajectory fitting formula generation process belong to two asynchronous processes that do not depend on each other and can work in different threads in software design.

[0074] Based on the above closed-loop tracking guiding method of the telescope, an embodiment of the present invention also provides a closed-loop tracking guiding system for the telescope, as Figure 3 shown, including:

[0075] A timing module, a data processing and control terminal, and a telescope. Among them, the data processing and control terminal includes a telescope control module and an image processing module, and the telescope includes a servo control module and a camera.

[0076] The timing module is respectively connected to the telescope control module and the camera, and provides time information through the timing module. The triggering frequency of the time information provided by the timing module and the acquisition frequency of the acquired images can be the same or different. When they are different, the triggering frequency of the time information provided by the timing module is an integer multiple of the image acquisition frequency.

[0077] The camera acquires images of the target observed by the telescope according to the acquisition frequency, and sends the acquired target images to the image processing module connected to the camera. The frequency of sending the target images is also the acquisition frequency .

[0078] The image processing module receives the target images sent by the camera, calculates the target off-target amount in the target images based on the target images, and sends the target off-target amount to the telescope control module connected to the image processing module. Calculating the corresponding target off-target amount based on the target images belongs to a mature existing technology.

[0079] The servo control module is also connected to the telescope control module, and sends encoder pointings to the telescope control module. The encoder pointings include azimuth encoder pointings and elevation encoder pointings. The frequency of sending the encoder pointings is .

[0080] The telescope control module calculates the target reference guiding pointing based on the received encoder pointings, target off-target amount, and time information, further obtains the actual guiding pointing for the next guiding cycle, and encodes it into a control instruction to be sent to the servo control module at a specified time. The servo control module operates at a frequency Receive the actual guiding direction and control the telescope to smoothly move to the specified direction within the upcoming telescope rotation cycle to guide the telescope to track the target.

[0081] Among them, the trigger frequency is greater than or equal to the guiding frequency at which the servo control module receives the actual guiding direction , and the trigger frequency is an integer multiple of the guiding frequency . Except for the above relationship, in the embodiments of the present invention, the trigger frequency , the frequency , the frequency and the camera frequency have no other dependency relationships.

[0082] It should be noted that in the actual application process, the telescope control module and the image processing module can be in one software, or in different software, can be in one terminal, or in different terminals, with higher flexibility and more convenient to implement.

[0083] For the overall structure of the above-mentioned closed-loop tracking and guiding system of the telescope, the main modules involved in the embodiments of the present invention are as Figure 1 shown. To reflect the modular characteristics of the telescope, for Figure 1 the various system modules involved, only the most basic and necessary communications are included, and complex functional coupling designs such as timing alignment are not included.

[0084] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0085] The above specific implementation manners of the present invention do not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and deformations made according to the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A closed-loop tracking and guiding method for a telescope, characterized in that, Including: S1: Preset trigger frequency , provide time information according to the trigger frequency , where represents the serial number of the time information; ​ S2: Predetermined reception frequency of the actual guiding direction , where the actual guiding direction is data for guiding the telescope to track the target, and the trigger frequency is an integer multiple of the reception frequency ; S3: Set , determine whether to trigger telescope guidance this time: If has a remainder of 0, then perform telescope guidance and proceed to the next step; If has a non-zero remainder, no telescope guidance is performed and the process ends; S4: Preset acquisition frequency , acquire the target image according to the acquisition frequency and calculate the target miss amount corresponding to the target image , where represents the azimuth target miss amount, and represents the pitch target miss amount; S5: Obtain the telescope encoder pointing closest to the current time information , where respectively represent the azimuth encoder pointing and the elevation encoder pointing; S6: Perform target trajectory fitting and calculate the target reference guidance direction : Q1: Calculate the approximate target direction ; Obtain the target direction information ; Add the target direction information to the head of the information queue , where the information queue is a collection composed of target direction information arranged in the order of time information; Q2: Set the quantity threshold , and determine the target pointing information in the message queue to see if its quantity is less than or equal to the quantity threshold : If so, keep the message queue unchanged; Otherwise, delete the information queue The target pointing information at the middle and end , and obtain a new information queue ; Q3: Based on the information queue , obtain the trajectory fitting formula: ； Among them, represents the azimuth value or pitch value of the target reference guidance direction , , and represents the coefficient of the azimuth value trajectory fitting formula of the target reference guidance direction or the coefficient of the pitch value trajectory fitting formula of the target reference guidance direction ; Q4: Solve the coefficients by the least squares method , and , and obtain the target reference guiding direction ; S7: Superimpose the target reference guidance direction and the target miss amount , and solve for the actual guidance direction , and use the actual guidance direction to guide the telescope.

2. The closed-loop tracking and guiding method of the telescope according to claim 1, wherein The trigger frequency is an integer multiple of the acquisition frequency.

3. The closed-loop tracking and guiding method of the telescope according to claim 1, characterized in that, The trigger frequency is set to 100 Hz.

4. The closed-loop tracking and guiding method of the telescope according to claim 1, characterized in that, The quantity threshold is set to 20.

5. A closed-loop tracking and guiding system for a telescope, which guides the telescope based on the closed-loop tracking and guiding method for a telescope according to any one of claims 1 to 4, characterized in that, Including: A time service module, a servo control module, a camera, a telescope control module, and an image processing module; The time service module provides time information; The camera acquires a target image and sends the target image to the image processing module; The image processing module calculates the target miss distance in the target image based on the target image, and sends the target miss distance to the telescope control module; The servo control module receives the actual guiding direction to guide the telescope to track the target, and sends the encoder direction to the telescope control module; The telescope control module calculates the actual guiding direction based on the encoder direction, the target miss distance, and the time information, and sends it to the servo control module.

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