Medium and high orbit target positioning method and all-time telescope target positioning system

Abstract

The invention relates to the technical field of photoelectric telescope precision measurement, in particular to a medium and high orbit target positioning method and an all-time telescope target positioning system, an observation trajectory is determined according to the number of two rows of orbits of a target, a telescope is guided to track the target according to the observation trajectory, and observation data of the target is recorded; selecting a plurality of fixed stars for assisting target positioning, guiding the telescope to track each fixed star in sequence, and recording observation data of each fixed star; and establishing a telescope error equation, performing curved surface error fitting according to the observation data, and resolving the telescope error equation to obtain the actual direction of the target. According to the method, the neighborhood auxiliary positioning fixed star is automatically selected based on curved surface error fitting, the telescope error equation is solved by calculating the theoretical direction of the neighborhood fixed star, the direction error, the encoder and other information, and high-precision positioning of the small-view-field all-day telescope target is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric telescope precision measurement, and in particular relates to a medium- and high-orbit target positioning method and a full-time telescope target positioning system. Background Art

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

[0003] Traditional photoelectric telescopes used for nighttime observation mainly use visible light cameras with a large field of view. When observing space targets at night with good atmospheric transmittance, in addition to space targets, there will be a large number of stars used for astronomical positioning in the image. Unlike traditional photoelectric telescopes, all-day telescopes use short-wave infrared detectors with a small field of view, usually about 10′ diagonally. When observing space targets, not only is the signal-to-noise ratio low, but there are also insufficient stars in the field of view for astronomical positioning. Therefore, after observing a space target, the all-day telescope needs to observe the stars around the satellite and calculate the precise direction of the space target through a certain algorithm.

[0004] During the observation process, the pointing direction of medium and high orbit targets changes very little in a short period of time, while the pointing direction 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 medium earth orbit (MEO), which is usually about 2000km to 20000km from the earth's surface, and geostationary earth orbit (GEO), which is about 36000km from the earth's surface. In astronomical observation, common medium and high orbit targets mainly include artificial satellites and space debris. High earth orbit satellites are mainly used in mobile communication services. Currently, common high orbit satellites include China's Beidou and the United States' GPS. Medium earth orbit satellites are non-synchronous earth satellites, mainly used as a supplement and expansion of land mobile communication systems, and organically combined with ground public networks. Representative medium earth orbit satellites include China's Beidou MEO, the United States' Odyssey, and Russia's GLONASS. Space debris includes rocket bodies and satellite bodies that have completed their missions, rocket ejecta, discarded objects during the execution of space missions, and fragments generated by collisions between space objects. They are the main sources of pollution in the space environment.

[0006] In order to avoid collisions between artificial satellites and space debris, threats to space activities, and unnecessary economic losses, it is necessary to precisely locate artificial satellites and space debris to achieve the purpose of monitoring, early warning, and collision avoidance. The current common method of describing the orbital parameters of artificial objects (such as satellites) in Earth orbit is the Two-Line Element Set (TLE), which was developed by the North American Aerospace Defense Command (NORAD). It is an orbit encoding method that uses a suitable prediction model at a given epoch to estimate the position and velocity of the target at any point in the orbit with a certain accuracy. Since there is a certain error between the actual orbit of the space target and the orbit calculated by the two-line orbit element, and the error continues to increase with time. It is usually necessary to periodically measure and determine the motion orbit of the space target, and update its orbit element in time to prevent the target from being lost.

[0007] Since the astronomical positioning method requires that the same picture contain the space target and several stars for auxiliary positioning, but the field of view of the small-field all-day telescope is small and there are not 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 the Chinese invention patent publication number CN104133993A, published on November 5, 2014, and entitled "Star Matching Method Based on Error Vector Matching", a star matching method that can be used for small field of view optoelectronic devices is proposed. However, the small field of view referred to in the patent is not the field of view of an all-day telescope, which can still clearly present more than 10 stars in a single image. However, a single image of an all-day telescope generally shows one star, so the method proposed in the patent cannot be applied to an all-day 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", the spatial position relationship between the calibration star and the space debris is matched to achieve high-precision positioning of space debris. The advantage of this method is that its positioning accuracy for medium and high orbit targets is greatly improved compared with axis positioning. It is suitable for all-day observation telescopes. Only two stars are used in the positioning process, and the complexity of manual operation is not large. However, it was found in the experiment that the theoretical pointing of a single star contains a fixed and unknown systematic error, while the theoretical pointing of multiple stars exists in the form of random errors. Involving more stars in the positioning calculation can effectively reduce the influence of the single star system error, which is similar to the idea of ​​astronomical positioning of traditional large-field telescopes. However, the algorithm proposed in this patent cannot introduce more star calculation results to further reduce the influence of the single star system error. 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-day telescope target positioning system, which solves the coefficients of a given equation by calculating the theoretical pointing, pointing error and encoder information of neighboring stars, thereby obtaining a more accurate medium and high orbit target positioning result.

[0011] To achieve the above object, the technical solution created by the present invention is implemented as follows: The present invention provides a method for locating a medium- and high-orbit target, comprising: Calculate the observation trajectory based on the two-row orbit elements of the target; Select a number of stars for assisting in locating the target; Guide the telescope to track the target according to the observation trajectory and record the observation data of the target; Guide the telescope to track each star in turn and record the observation data of each star; The surface error fitting is performed based on the observation data of the target and each star to calculate the actual direction of the target.

[0012] Preferably, the observation trajectory includes: time, and theoretical directions corresponding to different times, and the theoretical directions include theoretical azimuth angle and theoretical pitch angle.

[0013] Preferably, the process of selecting stars is: Select a star with the smallest Euclidean distance from the theoretical pointing coordinate of the target; At least three stars located on a circle whose Euclidean distance from the theoretical pointing coordinates of the target is a first set threshold are selected.

[0014] Preferably, before selecting stars, the method further includes: in the selected star database, forming a star set from all stars whose Euclidean distance from the theoretically pointed coordinates of the target is less than a second set threshold, and selecting stars from the star set for auxiliary positioning of the target.

[0015] Preferably, 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.

[0016] Preferably, the observation data of each star includes at least: the observation time of the star, the orientation of the encoder when observing the star, and the theoretical orientation of the star.

[0017] Preferably, the process of surface error fitting is: 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.

[0018] Another aspect of the invention is to provide a full-time telescope target positioning system, which uses a medium- and high-orbit target positioning method to obtain the actual direction of the target to be observed.

[0019] Compared with the prior art, the invention can achieve the following beneficial effects: The present invention effectively solves the problem that high-precision positioning of the target cannot be achieved due to the small field of view of the small-field all-day telescope and the lack of sufficient stars in the field of view that can be used for astronomical positioning. The present invention automatically selects neighboring auxiliary positioning stars based on surface error fitting, solves the coefficients of the telescope error equation by calculating the theoretical pointing, pointing error and encoder information of the neighboring stars, and obtains the actual pointing of the target by calculating the encoder pointing without the influence of the off-target amount when observing the target and the encoder pointing error of the target. In the process of star selection, not only a larger number of auxiliary positioning stars are expanded to participate in the calculation, thereby improving the positioning accuracy, but also the star selection is automated, thus avoiding the complicated manual star selection process of the operator.

[0020] The present invention realizes the requirement of high-precision target positioning through automatic star selection and coefficient calculation of telescope error equation, and improves the practicability of high-orbit target positioning in small-field-of-view optoelectronic telescopes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 is a flowchart of medium and high orbit target positioning according to an embodiment of the present invention; Figure 2 It is a basic principle diagram of surface error fitting positioning provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the invention clearer, the invention is 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 invention and do not constitute a limitation to the invention. Similar components in different embodiments use associated similar component numbers. In the following embodiments, many detailed descriptions are to enable the invention to be better understood. 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 components, materials, and methods. In some cases, some operations related to the invention are not shown or described in the specification, in order to avoid the core part of the invention being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations according to the description in the specification and the general technical knowledge in the art.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to form various implementation methods. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0024] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the 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 on the 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 number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0025] 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.

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0027] See also Figure 1 In one embodiment of the present invention, a medium-high orbit target positioning method is provided, which is mainly used for medium-high orbit target positioning of a small field of view telescope system, wherein the medium-high orbit target refers to a target located in a medium earth orbit, which is usually about 2000km to 20000km from the earth's surface, and a target located in a geostationary orbit, which is usually about 36000km from the earth's surface. The target is usually an artificial satellite or space debris. The positioning process of the above medium-high orbit target is as follows: First, based on the two-row orbital elements of the medium and high orbit target to be measured, the observation trajectory of the target within the observation time is calculated. The observation trajectory includes: the observation time, the theoretical direction of the target at different times, or the theoretical direction sequence, the theoretical direction is the theoretical azimuth and the theoretical pitch angle. The method for obtaining the observation trajectory of the target is a prior art, and the specific calculation process is not described here. The acquisition of the observation trajectory can lay the foundation for subsequent positioning and observation tasks. The observation trajectory can determine the observation time of a target. The target theoretical orientation is expressed as ,in, express The target theoretical azimuth at time, express The target theoretical pitch angle at the moment.

[0028] In order to solve the problem of lack of sufficient number of auxiliary positioning stars in the observation field of view during the positioning of high-orbit targets in a small-field telescope system, an automatic star selection algorithm is designed in the embodiment of the present invention to expand the selection of multiple stars for auxiliary positioning of the target, and the number of selected stars is represented by n. In order to meet the needs of high-precision positioning of medium and high-orbit targets, a full-time telescope system usually needs to select 4-8 stars.

[0029] 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.

[0030] 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 amount of calculation for subsequent star selection, and vice versa.

[0031] 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.

[0032] See also Figure 2 , the specific process of selecting stars is: 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 .

[0033] b. Select three stars located on a circle with a 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: Use the star pointing calculation tool to calculate the positions 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 .

[0034] Use the star pointing calculation tool to calculate the positions 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 .

[0035] Use the star pointing calculation tool to calculate the positions 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 .

[0036] In the embodiment of the present invention, three stars are selected on the circumference, so the three selected reference points , and It is located exactly on the three vertices of the equilateral triangle.

[0037] For ease of expression, the observation time is recorded as , represents the observation time of the target, , , and represents the observation time of the star. Correspondingly, the theoretical direction of the target and the star is expressed as ,when When , it indicates the target theory orientation; when When , it indicates the theoretical direction of the star.

[0038] exist At this moment, the theoretical direction of the target contained in the observation trajectory obtained by calculating the two-row orbital elements is Guide the telescope to track the target and record the target's observation data, including the target's observation time , and the encoder direction when observing the target . express When observing the target at any time, the target direction obtained by the encoder on the telescope system is recorded as , referred to as the target encoder pointing to , The observed image in the telescope field of view at the moment is recorded as , where the pointer The target is in the observation image The impact of off-target amount.

[0039] It should be noted that when using a telescope to observe a target, the actual pointing (azimuth and angular pitch) of the telescope is unknown, and the actual pointing is the result that needs to be solved, but the encoder value is known, which is the encoder pointing provided by the telescope system when observing a target or star. The encoder pointing does not reflect the actual pointing of the telescope's observed target or star. Since the target or star cannot be guaranteed to be located in the center of the field of view during observation, and it will also be 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 pitch 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 as the external environment (such as temperature, humidity, atmospheric pressure, etc.) changes, the pointing error under the same encoder value will also change. Therefore, after observing the target to be measured and obtaining its encoder value, it is necessary to calculate the pointing error under the encoder value through the neighboring stars, and then obtain the actual pointing of the target to be measured.

[0040] exist Time, according to the stars Theoretical direction Guide the telescope to track the target and record the stars The observational data includes the stars Observation time , observe stars When the encoder points , and the theoretical direction of stars , The observation image at time is expressed as .

[0041] exist Time, according to the stars Theoretical direction Guide the telescope to track the target and record the stars The observational data includes the stars Observation time , observe stars When the encoder points , and the theoretical direction of stars , The observation image at time is expressed as .

[0042] exist Time, according to the stars Theoretical direction Guide the telescope to track the target and record the stars The observational data includes the stars Observation time , observe stars When the encoder points , and the theoretical direction of stars , The observation image at time is expressed as .

[0043] exist Time, according to the stars Theoretical direction Guide the telescope to track the target and record the stars The observational data includes the stars Observation time , observe stars When the encoder points , and the theoretical direction of stars , The observation image at time is expressed as .

[0044] When applying the editing algorithm, you can also Figure 1 As shown in , after a star is selected, the telescope is guided to track the star and record the observation data, and the conditional judgment function is used to realize the selection and tracking of each star.

[0045] When a telescope observes a target or star, the target is usually not imaged in the center of the field of view. Therefore, the telescope encoder pointing direction will be affected by the miss distance of the target or star in the corresponding observation image. Therefore, the encoder pointing direction directly shown by the telescope is likely to be different from the encoder pointing direction without miss distance influence. The encoder pointing direction without miss distance influence here refers to the actual pointing direction that the encoder should achieve without miss distance influence. Therefore, it is necessary to calculate the miss distance of the target and each star through image processing algorithm and telescope optical parameters. The target extraction and miss distance related algorithms are mature algorithms in the field of telescope image processing, which are beyond the scope of discussion of the present invention and will not be described in detail here.

[0046] Ignore external disturbances during observation and set each observation time The encoder points to Add the miss distance of the corresponding target or star in the observed image at that moment to obtain the encoder pointing direction without miss distance influence at each observation time. , the calculation formula for the encoder pointing without the influence of the miss amount is: .

[0047] In actual observation, the target Theoretical orientation of the moment It is calculated by the two orbital elements. The theoretical direction of the target calculated by this method is Actual direction to the target There is a certain deviation between them, so the theoretical pointing of the target cannot be considered equal to the actual pointing. The theoretical pointing of the star is calculated by the 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 this moment is equal to the theoretical pointing. Therefore, the star pointing data can be used for target calibration.

[0048] Each observation time Encoder pointing without miss-target effect , Subtracting the theoretical direction of the corresponding star at that moment, we get to Encoder pointing error ,in, represents the encoder azimuth error, The encoder pitch angle error is expressed as follows: .

[0049] The telescope error equation is established based on the surface error fitting: ; in, , , , , and are coefficients, represents the azimuth, Indicates the pitch angle.

[0050] The telescope error equation shows that within a small encoder pointing range, when the telescope encoder value is The error between the encoder pointing and the actual pointing.

[0051] and Both are 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: The two equations in the telescope error equation are unified as: .

[0052] and The unified expression is .

[0053] Use the following formula To solve: ; in, , , .

[0054] Bring the encoder pointing direction of each star without the effect of off-target amount into A, to The encoder pointing error is introduced In the solution , that is, , , , , and .

[0055] Then point the encoder that is not affected by the miss amount when observing the target to Substituting the telescope error equation into the target encoder pointing error can be obtained .

[0056] The actual pointing of the target is further calculated by the encoder pointing without the effect of the miss amount when observing the target and the encoder pointing error of the target, and the actual pointing of the target is obtained. The actual direction of the goal at all times , The calculation formula is: .

[0057] In the embodiment of the present invention, only four stars are selected for auxiliary positioning. In actual measurement, the more auxiliary positioning stars are involved in the calculation, the higher the accuracy and confidence of the actual pointing of the target. But on the contrary, the more auxiliary positioning stars are involved in the calculation, the more time-consuming and program design complexity of a single target to be measured will be. Therefore, it should be selected according to the actual situation when using it. If you want to select more auxiliary positioning stars to participate in the calculation, you can select more stars uniformly in the same circle according to a certain rule when selecting stars, or design multiple different first set thresholds to select more stars on multiple circles according to a certain rule. Since different numbers of auxiliary positioning stars have different selection rules, different numbers of selected stars will affect , and The values ​​are 3°, 2.6° and 1.5°. The above numbers can be calculated based on the selected number of stars and geometric relationships, and will not be explained one by one here.

[0058] The high-orbit target positioning method provided in the embodiment of the present invention is applied to the all-day telescope target positioning system. The method is used to obtain the actual direction of the target to be observed, so as to achieve high-precision target positioning of the all-day telescope under small field of view conditions, thereby solving the problem that the existing positioning system is limited by the field of view.

[0059] In short, the above description is only a preferred embodiment of this specification and is not intended to limit the protection scope of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this specification shall be included in the protection scope of this specification.

[0060] The systems, devices, modules or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, the computer may 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 a combination of any of these devices.

[0061] 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 process, method, commodity 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 process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0062] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0063] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some 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: Calculate the observation trajectory based on the two-row orbit elements of the target; selecting a plurality of stars for assisting in positioning the target; 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: The observation trajectory includes: time, and theoretical directions corresponding to different times, and the theoretical directions include theoretical azimuth angle and theoretical elevation angle.

3. The medium-high rail target positioning method according to claim 2, characterized in that: The process of selecting stars is: Selecting a star with the smallest Euclidean distance from the theoretical pointing coordinate of the target; At least three stars located on a circle whose Euclidean distance from the theoretical pointing coordinates of the target is a first set threshold are selected.

4. The medium and high rail target positioning method according to claim 3, 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.

5. 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.

6. The medium-high rail target positioning method according to claim 5, 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.

7. The medium-high rail target positioning method according to claim 6, 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.

8. 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 7.

Images