A Medium and High Orbit Target Positioning Method and an All-Weather Telescope Target Positioning System

Abstract

The present invention relates to the technical field of precise measurement of optoelectronic telescopes, and specifically provides a method for positioning medium and high-orbit targets and an all-weather telescope target positioning system. The observation trajectory is determined according to the two-line orbital elements of the target, the telescope is guided to track the target according to the observation trajectory, and the observation data of the target are recorded; multiple stars for assisting target positioning are selected, the telescope is guided to track each star in turn, and the observation data of each star are recorded; a telescope error equation is established, surface error fitting is performed based on the above-mentioned observation data, the telescope error equation is solved, and the actual pointing of the target is obtained. The present invention automatically selects neighboring auxiliary positioning stars based on surface error fitting, and solves the telescope error equation by calculating information such as the theoretical pointing, pointing error, and encoder of the neighboring stars, so as to achieve high-precision positioning of small-field all-weather telescope targets.

Description

Technical Field

[0001] The present invention belongs to the technical field of precise measurement of optoelectronic telescopes, and particularly relates to a method for positioning medium and high orbit targets and an all-weather telescope target positioning system. Background Art

[0002] In recent years, telescopes that can be used for daytime observation based on the infrared band have gradually become the key research direction of scientific research institutions at home and abroad. At present, an all-weather telescope that can observe and position low-orbit, medium-orbit, high-orbit satellites and other types of targets during the day and at night has been successfully developed.

[0003] Traditional optoelectronic telescopes used for night observation mainly use visible light cameras and have a large field of view. When observing space targets under the condition of good atmospheric transmittance at night, there will be a large number of stars for astronomical positioning in the image in addition to the space targets. Different from traditional optoelectronic telescopes, all-weather telescopes use short-wave infrared detectors and have a small field of view, usually about 10' in diagonal. When observing space targets, not only is the signal-to-noise ratio low, but there are also not enough stars for astronomical positioning in the field of view. Therefore, after observing a space target, the all-weather telescope needs to observe the stars around the satellite and calculate the precise pointing of the space target through a certain algorithm.

[0004] During the observation process, due to the small change in the pointing of medium and high orbit targets in a short time, while the pointing of low orbit targets changes greatly. Therefore, for small-field-of-view optoelectronic telescopes, the measurement methods for low orbit targets and medium and high orbit targets are quite different.

[0005] Medium and high orbits are divided into the Medium Earth Orbit (MEO) which is usually about 2000 km to 20000 km from the Earth's surface and the Geostationary Earth Orbit (GEO) which is about 36000 km from the Earth's surface. In astronomical observations, common medium and high orbit targets mainly include artificial satellites and space debris. High Earth orbit satellites are mainly used for mobile communication services. Currently, common high orbit satellites such as Beidou in China and GPS in the United States; Medium Earth orbit satellites are non-synchronous satellites of the Earth and are mainly used as a supplement and extension of the land mobile communication system, and are organically combined with the ground public network. Representative Medium Earth orbit satellites include Beidou MEO in China, Odyssey in the United States, and GLONASS in Russia. Space debris includes the rocket bodies and satellite bodies that have completed their missions, the ejecta of rockets, the discarded objects during space missions, and the fragments generated by the collision between space objects, etc., and is the main pollution source of the space environment.

[0006] To avoid collisions between artificial satellites and space debris, which pose threats to space activities and result in unnecessary economic losses, it is necessary to precisely locate artificial satellites and space debris to achieve the purposes of monitoring, early warning, and collision avoidance. Currently, the common way to describe the orbital parameters of artificial objects (such as satellites) in Earth's orbit is the Two-Line Element Set (TLE). Developed by the North American Aerospace Defense Command (NORAD), it is an orbital encoding method. Using an appropriate prediction model at a given epoch, the position and velocity of the target at any point on the orbit can be estimated with a certain accuracy. However, there are certain errors between the actual operating orbit of the space target and the orbit calculated by the two-line orbital elements, and these errors increase over time. Therefore, it is usually necessary to periodically measure and determine the orbit of the space target and update its orbital elements in a timely manner to prevent the loss of the target.

[0007] Since the astronomical positioning method requires the presence of the space target and several auxiliary positioning stars in the same image, but the field of view of the small field-of-view all-sky telescope is small and lacks enough stars in the field of view, how to accurately locate medium and high-orbit space targets has become an important problem to be solved.

[0008] In Chinese Patent Publication No. CN104133993A, published on November 5, 2014, with the patent name "Star Matching Method Based on Error Vector Matching", a star matching method applicable to small field-of-view optoelectronic devices was proposed. However, the small field of view referred to in this patent is not of the same order as that of the all-sky telescope, and more than 10 stars can still be clearly presented in a single image. Generally, only one star appears in a single image of the all-sky telescope, so the method proposed in this patent is not applicable to the all-sky telescope.

[0009] In the Chinese invention patent publication number CN117870647A, the publication date is April 12, 2024, and the patent name is "A High-Precision Positioning Method and System Based on a Ground-Based Optical Telescope". By matching the spatial position relationship between calibration stars and space debris, high-precision positioning of space debris is achieved. The advantage of this method is that its positioning accuracy for medium and high-orbit targets has a significant improvement compared to axis system positioning. It is applicable to all-sky observation telescopes. Only 2 stars are used during the positioning process, and the complexity of manual operation is not high. However, it is found during the experiment that the theoretical pointing of a single star contains fixed and unknown systematic errors, while the theoretical pointing of multiple stars exists in the form of random errors. Incorporating more stars into the positioning calculation can effectively reduce the influence of the systematic errors of a single star, which is similar to the idea of astronomical positioning of traditional large-field-of-view telescopes. However, the algorithm proposed in this patent cannot introduce the calculation results of more stars to further reduce the influence of the systematic errors of a single star. Summary of the Invention

[0010] In view of this, the present invention aims to provide a medium and high-orbit target positioning method and an all-sky telescope target positioning system. By calculating information such as the theoretical pointing, pointing error, and encoder of neighboring stars to solve the coefficients of a given equation, a higher-precision medium and high-orbit target positioning result can be obtained.

[0011] To achieve the above object, the technical solution of the present invention is realized as follows:

[0012] On the one hand, the present invention provides a medium and high-orbit target positioning method, including:

[0013] Calculating the observation trajectory according to the two-line orbital elements of the target;

[0014] Selecting multiple stars for assisting in positioning the target;

[0015] Guiding the telescope to track the target according to the observation trajectory and recording the observation data of the target;

[0016] Guiding the telescope to track each star in turn and recording the observation data of each star;

[0017] Performing surface error fitting based on the observation data of the target and the observation data of each star to calculate the actual pointing of the target.

[0018] Preferably, the observation trajectory includes: time, and the corresponding theoretical pointing at different times, and the theoretical pointing includes the theoretical azimuth angle and the theoretical elevation angle.

[0019] Preferably, the process of selecting stars is as follows:

[0020] Selecting a star with the smallest Euclidean distance from the theoretical pointing coordinates of the target;

[0021] Select at least three stars located on a circle with an Euclidean distance from the theoretical pointing coordinates of the target being the first set threshold.

[0022] Preferably, before selecting the stars, it further includes: in the selected star database, forming a star set consisting of all stars with an Euclidean distance from the coordinates of the theoretical pointing of the target less than the second set threshold, and selecting stars for assisting in positioning the target within the star set.

[0023] Preferably, the observation data of the target at least includes: the observation time of the target, and the encoder pointing when observing the target.

[0024] Preferably, the observation data of each star at least includes: the observation time of the star, the encoder pointing when observing the star, and the theoretical pointing of the star.

[0025] Preferably, the process of surface error fitting is as follows:

[0026] According to the positions of the target and each star in the corresponding observation image, calculate the off-target amount of the target and each star, where the observation time corresponding to the observation image is represented as , represents the observation time of the target, , … represents the observation time of the star, and n represents the number of selected stars;

[0027] Add the encoder pointing at each observation time to the off-target amount of the corresponding target or star to obtain the encoder pointing of the corresponding target or star without the influence of off-target amount at each observation time;

[0028] Subtract the encoder pointing of each star without the influence of off-target amount at each observation time from the theoretical pointing of the corresponding star to obtain the encoder pointing error at each observation time , where, represents the encoder azimuth error, represents the encoder pitch error;

[0029] Based on the surface error fitting, establish the telescope error equation as:

[0030] ;

[0031] where, , , , , and are all coefficients, represents the encoder azimuth, represents the encoder pitch;

[0032] The encoder pointing of the star without the influence of off-target amount and the encoder pointing error between the star and the encoder at each observation time are solved by the least squares method. 、 、 、 、 and ;

[0033] Bringing the encoder pointing of the target without the influence of off-target amount when observing the target into the telescope error equation can obtain the encoder pointing error of the target , and the actual pointing of the target is calculated from the encoder pointing of the target without the influence of off-target amount and the encoder pointing error of the target when observing the target.

[0034] On the other hand, the present invention provides an all-day telescope target positioning system, which uses the medium and high orbit target positioning method to obtain the actual pointing of the target to be observed.

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

[0036] The present invention effectively solves the problem that due to the small field of view of the all-day telescope with a small field of view and the lack of enough stars available for astronomical positioning in the field of view, it is impossible to achieve high-precision target positioning. Based on the curved surface error fitting, neighboring auxiliary positioning stars are automatically selected, and the coefficients of the telescope error equation are solved by calculating the theoretical pointing, pointing error, encoder and other information of the neighboring stars. The actual pointing of the target is obtained by calculating the encoder pointing without the influence of off-target amount and the encoder pointing error of the target when observing the target; during the process of selecting stars, not only a larger number of auxiliary positioning stars are expanded to participate in the calculation, improving the positioning accuracy, but also the star selection is automated, avoiding the complex manual star selection process of the operator.

[0037] The present invention realizes the high-precision target positioning requirement through automated star selection and calculation of the coefficients of the telescope error equation, and improves the practicability of medium and high orbit target positioning of small field of view optoelectronic telescopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0039] Figure 1 is a flowchart of medium and high orbit target positioning according to an embodiment of the present invention;

[0040] Figure 2 is a basic schematic diagram of curved surface error fitting positioning according to an embodiment of the present invention. Detailed implementation manners

[0041] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below 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 details are described 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, or methods. In some cases, some operations related to the present invention are not shown or described in the specification, in order to avoid the core part of the present invention being overwhelmed by excessive description. 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 the general technical knowledge in the art.

[0042] 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 implementation manners. At the same time, the steps or actions in the method description can also be reordered or adjusted in an obvious manner by those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0043] 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, and are 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 thus cannot be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0046] Please refer to Figure 1 , in an embodiment of the present invention, a method for positioning medium and high orbit targets is provided, which is mainly applied to the positioning of medium and high orbit targets in a small field of view telescope system. Among them, medium and high orbit targets refer to targets located on medium earth orbits usually about 2000 km to 20000 km from the earth's surface, and targets located on geostationary orbits usually about 36000 km from the earth's surface. The targets are usually artificial satellites or space debris, etc. The positioning process for the above medium and high orbit targets is as follows:

[0047] First, according to the two-line orbital elements of the medium and high orbit target to be measured, calculate the observation trajectory of the target during the observation time. The observation trajectory includes: the observation time, the theoretical pointing of the target at different times, or the theoretical pointing sequence, and the theoretical pointing is the theoretical azimuth angle and the theoretical elevation angle. The method for obtaining the observation trajectory of the target is a prior art, and the specific calculation process will not be elaborated here. The acquisition of the observation trajectory can lay a foundation for subsequent positioning and observation tasks. From the observation trajectory, a target observation moment of the target theoretical pointing can be determined, and this theoretical pointing is expressed as , where represents the target theoretical azimuth angle at the moment, and represents the target theoretical elevation angle at the

[0048] To solve the problem that there are not enough auxiliary positioning stars in the observation field of view during the positioning process of medium and high orbit targets in a small field of view telescope system, an automatic star selection algorithm is designed in the embodiment of the present invention to expand the selection of multiple stars for assisting in positioning the target. The number of selected stars is represented by n. To meet the requirements of high-precision positioning of medium and high orbit targets, the all-weather telescope system usually needs to select 4 - 8 stars.

[0049] Before the specific star selection, it is necessary to select a star database and perform a preliminary rough selection in the star database to reduce the amount of calculation in the subsequent selection process. In the embodiment of the present invention, the star database uses the latest Gaia star catalog (as of now, the latest Gaia star catalog is Gaia DR3), performs a rough selection of stars from the Gaia DR3 database, and defines the rough selection results as a set S.

[0050] The specific rough selection process is as follows: First, Always find the theoretical direction of the target in the Gaia DR3 database All stars whose coordinate Euclidean distance is less than 5° are defined as set S. It should be noted that the Euclidean distance here refers to the distance in a two-dimensional plane coordinate system with azimuth and elevation as x and y axes respectively. All stars with a Euclidean distance less than 5° (the second set threshold), that is, the coordinate points of the stars in the set S in the coordinate system, are within a circular area with the target theoretical pointing coordinate as the center and a radius of 5°. Among them, the method of obtaining the theoretical pointing of stars is an existing technology. The commonly used star pointing calculation tool is the SOFA (Standards of Fundamental Astronomy) code toolkit. The telescope control system can accurately calculate the position of the star at the station at that moment by inputting UTC time, station address and star information (right ascension, declination, etc.), or obtain the theoretical pointing of stars that guide the telescope to observe stars (that is, the azimuth and elevation angle of the star). In this process, the threshold for the rough selection of stars is designed to be 5°. The threshold can be adjusted according to the observation and positioning requirements. The larger the threshold, the greater the calculation amount for subsequent star selection, and vice versa.

[0051] According to the basic principle of neighborhood surface error fitting positioning, n stars are further selected from the set S for auxiliary positioning of the target. In the embodiment of the present invention, n = 4. Since the embodiment of the present invention is aimed at the observation and positioning of high-orbit targets in a small-field telescope system, the target and the selected 4 stars will not appear in the same field of view at the same time, so it is necessary to shoot and select stars in different time periods.

[0052] See also Figure 2 , the specific process of selecting stars is:

[0053] a. First, select a star with the smallest Euclidean distance from the theoretical pointing coordinates of the target. :Use the star pointing calculation tool to calculate the position of all stars in the set S Theoretical direction of the moment, and find The star with the smallest Euclidean distance , and its theoretical direction is recorded as .

[0054] b. Select three stars located on a circle with an Euclidean distance of 3° (the first set threshold) from the theoretical pointing coordinates of the target. The first set threshold can also be adjusted according to the actual positioning accuracy requirements. The selection process of these three stars is as follows:

[0055] Use the star pointing calculation tool to calculate the theoretical pointing of all stars in set S at time, and find the star with the smallest Euclidean distance from the coordinates of , and its theoretical pointing is denoted as .

[0056] Use the star pointing calculation tool to calculate the theoretical pointing of all stars in set S at time, and find the star with the smallest Euclidean distance from the coordinates of , and its theoretical pointing is denoted as .

[0057] Use the star pointing calculation tool to calculate the theoretical pointing of all stars in set S at time, and find the star with the smallest Euclidean distance from the coordinates of , and its theoretical pointing is denoted as .

[0058] In the embodiment of the present invention, three stars are selected on the circle, so the three selected references , and happen to be located at the three vertices of an equilateral triangle.

[0059] For the sake of convenience of expression, the observation time is denoted as , represents the observation time of the target, , , and represent the observation times of the stars. Correspondingly, the theoretical pointings of the target and the stars are expressed as . When , it represents the target theoretical pointing; when , it represents the star theoretical pointing.

[0060] At time, the target theoretical pointing included in the observation trajectory calculated according to the two-line orbital elements guides the telescope to track the target, and records the observation data of the target, including the observation time of the target, and the encoder pointing when observing the target. represents ​​​When observing the target at a certain moment, the target pointing obtained by the encoder on the telescope system is denoted as , which is simply referred to as the encoder pointing of the target . The observed image within the telescope's field of view at a certain moment is denoted as , where this pointing is affected by the off - target amount of the target in the observed image .

[0061] It should be noted that when using the telescope to observe the target, the actual pointing (azimuth and elevation angle) of the telescope is unknown, and this actual pointing is the result that needs to be solved. However, the encoder value is known, and this encoder value is the encoder pointing provided by the telescope system when observing the target or a star. This encoder pointing cannot reflect the actual pointing of the telescope when observing the target or a star. Since it cannot be guaranteed that the target or a star is located at the center of the field of view during observation and is also affected by external interference, there is an error between the encoder pointing directly provided by the telescope system and the actual pointing of the observed target or star. This error is called the encoder pointing error (azimuth error and elevation error). The pointing error changes continuously with the change of the telescope encoder value, but there is no fixed rule for the change of the pointing error. And with the change of the external environment (such as temperature, humidity, atmospheric pressure, etc.), the pointing error under the same encoder value will also change accordingly. Therefore, after observing the target to be measured and obtaining its encoder value, it is necessary to calculate the pointing error at this encoder value through neighboring stars, and then obtain the actual pointing of the target to be measured.

[0062] At moment, according to the theoretical pointing of the star , guide the telescope to track the target, and record the observation data of the star . The observation data includes the observation time of the star , the encoder pointing when observing the star , and the theoretical pointing of the star, The observed image at the moment is represented as .

[0063] At moment, according to the theoretical pointing of the star , guide the telescope to track the target, and record the observation data of the star . The observation data includes the observation time of the star , the encoder pointing when observing the star , and the theoretical pointing , The observed image at a moment is represented as .

[0064] At moment, according to the theoretical pointing of the star guide the telescope to track the target, record the observed data of the star , and the observed data includes the observation time of the star , the encoder pointing when observing the star , and the theoretical pointing of the star, The observed image at a moment is represented as .

[0065] At moment, according to the theoretical pointing of the star guide the telescope to track the target, record the observed data of the star , and the observed data includes the observation time of the star , the encoder pointing when observing the star , and the theoretical pointing of the star, The observed image at a moment is represented as .

[0066] When specifically applying the editing algorithm, it can also be as shown in Figure 1 . After selecting a star, guide the telescope to track the star and record the observed data, and use the conditional judgment function to realize the selection and tracking of each star.

[0067] Since when the telescope observes the target and the star, the target usually does not image at the center of the field of view, so at this time the encoder pointing of the telescope will be affected by the off-target amount of the target or the star in the corresponding observed image. Therefore, the encoder pointing directly shown by the telescope is probably different from the encoder pointing without the influence of the off-target amount. Here, the encoder pointing without the influence of the off-target amount refers to the pointing that the encoder should actually reach without the influence of the off-target amount. Therefore, it is necessary to calculate the off-target amounts of the target and each star through the image processing algorithm and the optical parameters of the telescope . The algorithms related to target extraction and off-target amount are mature algorithms in the field of telescope image processing and are not within the scope of discussion of the present invention, so they will not be elaborated here.

[0068] Ignoring the external disturbances during observation, the encoder pointing at each observation time Add the offset amounts of the corresponding targets or stars in the observed images at that moment to obtain the encoder pointing without the influence of offset amounts for each observation time. , the calculation formula for the encoder pointing without the influence of offset amounts is:

[0069] .

[0070] In actual observations, the theoretical pointing of the target at the moment is calculated from its two-line orbital elements. The theoretical pointing of the target calculated by this method has a certain deviation from the actual pointing of the target. Therefore, it cannot be considered that the theoretical pointing of the target is equal to the actual pointing. The theoretical pointing of the star is calculated by a star pointing calculation tool. The error between the theoretical pointing of the star calculated by this method and the actual pointing of the star is small and within an acceptable range. So, it can be approximately considered that the actual pointing of the star at that moment is equal to the theoretical pointing. Therefore, the pointing data of the star can be used for target calibration.

[0071] Subtract the encoder pointing without the influence of offset amounts of the star for each observation time , from the theoretical pointing of the corresponding star at that moment to obtain to the encoder pointing error , where represents the encoder azimuth error, represents the encoder elevation error. The calculation formula for the encoder pointing error is:

[0072] .

[0073] Based on the surface error fitting, establish the telescope error equation as:

[0074] ;

[0075] where , , , , and are all coefficients, represents the azimuth angle, represents the elevation angle.

[0076] The telescope error equation indicates that within a relatively small encoder pointing interval range, when the telescope encoder value is , the error between this encoder pointing and the actual pointing.

[0077] and are both coefficients to be solved, and the solution methods for the two sets of coefficients are the same. The two sets of coefficients are solved by the least squares method. The specific process is as follows:

[0078] Unify the two equations in the telescope error equation as:

[0079] .

[0080] and are unified as .

[0081] Use the following formula to solve :

[0082] ;

[0083] where , , .

[0084] Substitute the encoder pointing without the influence of off-target amount of each star into A, and substitute the encoder pointing errors from to into . Solve to get , that is, solve to get , , , , and .

[0085] Then substitute the encoder pointing without the influence of off-target amount when observing the target into the telescope error equation to obtain the encoder pointing error of the target.

[0086] Furthermore, calculate the actual pointing of the target from the encoder pointing without the influence of off-target amount when observing the target and the encoder pointing error of the target, and obtain the actual pointing of the target at time , The calculation formula is:

[0087] .

[0088] In the embodiments of the present invention, only four stars for auxiliary positioning are selected. In actual measurement, the more auxiliary positioning stars involved in the calculation, the higher the accuracy and confidence of obtaining the actual pointing of the target. However, conversely, the more auxiliary positioning stars involved in the calculation, the longer the measurement time for a single target to be measured and the higher the complexity of program design. Therefore, a trade-off should be made according to the actual situation when using. If you want to select more auxiliary positioning stars to participate in the calculation, you can, when selecting the selected stars, evenly select a larger number of stars in the same circle according to a certain rule, or design multiple different first set thresholds and select a larger number of stars on multiple circles according to a certain rule. Since the selection rules for different numbers of auxiliary positioning stars are different, different numbers of selected stars will affect , and the values of 3°, 2.6° and 1.5° in. The above numbers can be specifically calculated according to the number of selected stars and geometric relationships, and will not be elaborated one by one here.

[0089] Applying the high-orbit target positioning method provided by the embodiments of the present invention to the all-weather telescope target positioning system, and using this method to obtain the actual pointing of the target to be observed, it is possible to achieve high-precision target positioning of the all-weather telescope under small field of view conditions, and solve the drawback that the existing positioning system is limited by the field of view.

[0090] In summary, the above are only the preferred embodiments of this specification, and are not used to limit the protection scope of this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of this specification shall be included within the protection scope of this specification.

[0091] The system, device, module or unit illustrated by the above one or more embodiments can be specifically implemented by a computer chip or entity, or by a product with a certain function. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0092] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of another identical element in the process, method, commodity or device including the said element.

[0093] Each embodiment in this specification is described in a progressive manner. For the identical or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and reference can be made to the relevant parts in the method embodiments for the relevant content.

[0094] The specific embodiments of this specification are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A method for locating a medium- and high-orbit target, characterized in that: include: Calculating an observation trajectory according to two orbit elements of the target, wherein the observation trajectory includes: time, and theoretical directions corresponding to different times, wherein the theoretical directions include theoretical azimuth and theoretical elevation; A plurality of stars are selected for assisting the positioning of the target. The process of selecting the stars is as follows: Selecting a star with the smallest Euclidean distance from the theoretical pointing coordinate of the target; selecting at least three stars located on a circle whose Euclidean distance from the theoretical pointing coordinates of the target is a first set threshold; guiding the telescope to track the target according to the observation trajectory, and recording the observation data of the target; Guide the telescope to track each star in turn and record the observation data of each star; Surface error fitting is performed based on the observation data of the target and the observation data of each star to calculate the actual direction of the target.

2. The medium-high rail target positioning method according to claim 1, characterized in that: Before selecting stars, the method also includes: in the selected star database, all stars whose Euclidean distances from the theoretically pointed coordinates of the target are less than a second set threshold value are formed into a star set, and stars for auxiliary positioning of the target are selected from the star set.

3. The medium-high rail target positioning method according to claim 1, characterized in that: The observation data of the target includes at least: the observation time of the target and the direction of the encoder when observing the target.

4. The medium and high rail target positioning method according to claim 3, characterized in that: The observation data of each star includes at least: the observation time of the star, the direction of the encoder when observing the star, and the theoretical direction of the star.

5. The medium-high rail target positioning method according to claim 4, characterized in that: The process of surface error fitting is as follows: According to the positions of the target and each star in the corresponding observation image, the miss distance of the target and each star is calculated, where the observation time corresponding to the observation image is expressed as , represents the observation time of the target, , … represents the observation time of the star, and n represents the number of selected stars; The encoder pointing at each observation time is added to the miss distance of the corresponding target or star to obtain the encoder pointing of the target or star corresponding to each observation time without the miss distance influence; Subtract the encoder pointing error of the star at each observation time without the effect of the miss amount from the theoretical pointing error of the corresponding star to obtain the encoder pointing error at each observation time. ,in, represents the encoder azimuth error, Indicates the encoder pitch angle error; The telescope error equation is established based on the surface error fitting: ； in, , , , , and are coefficients, represents the encoder azimuth, Indicates the encoder pitch angle; Based on the encoder pointing of the star without the effect of the miss amount at each observation time and the encoder pointing error of the star, the least squares method is used to solve , , , , and ; Point the encoder to the direction where the target is not affected by the miss amount when observing the target Substituting the telescope error equation into the target encoder pointing error can be obtained The actual pointing of the target is calculated by the encoder pointing of the target without the influence of the miss amount when observing the target and the encoder pointing error of the target.

6. A full-time telescope target positioning system, characterized in that: The actual direction of the target to be observed is obtained by using the medium- and high-orbit target positioning method described in any one of claims 1 to 5.

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