A high-precision positioning method for astronomical devices

Abstract

The present invention discloses a high-precision positioning method for an astronomical device. The method comprises a telescope system mounted on a two-dimensional direct-drive turntable. The rear end of the telescope is equipped with an autofocus mount, which is connected to a CCD camera. An electronic compass is mounted above the CCD camera. The electronic compass is used to initially determine the zero position of the telescope in both the horizontal and north directions. The CCD camera is then used to control the two-dimensional turntable to rotate and scan within a set area near a target star. Once the target star appears in the CCD field of view, image processing and calculations are used to determine the device's relatively high-precision positioning at that location. The method has a high degree of automation, with the entire process performed by software, and can effectively achieve high-precision positioning of the device.

Description

Technical Field

[0001] The invention belongs to the field of automatic control, and in particular relates to a high-precision positioning method for a device. Background Art

[0002] In astronomical observations, it is often necessary to stably track a specific star for astronomical photography or to measure certain parameters. The observed position of a star at a certain location and time can be calculated by obtaining parameters such as right ascension and declination from star catalogs. Right ascension and declination can be obtained from star catalogs or astronomical almanacs. Common star catalogs include the Smithsonian Institutional Observatory (SAO) and the Hipparcos Index (HIP). Because stars are relatively far from the observation site and the telescope's field of view is relatively small, in order to accurately and stably track the target star, the tracking device must have a high level of tracking accuracy and precise positioning. Specifically, the horizontal zero position and pitch zero position of the telescope at a specific location must be accurate.

[0003] For common astronomical equipment observations, stars (such as the North Star) are generally used to position the observation equipment. This method involves installing a finderscope directly above the telescope, adjusting the angle of the finderscope so that the finderscope and telescope are coaxial, and the field of view of the finderscope is larger than that of the telescope. When a star is observed in the finderscope, the star is moved to the middle position of the finderscope by adjusting the horizontal and pitch angles of the device, so that the star can be seen in the telescope. The device is then further fine-tuned so that the star appears in the center of the telescope's field of view, and the position of the device at this time is read. At the same time, the star catalog combined with the algorithm calculates the azimuth and pitch angles of the star observation at this time. The horizontal angle, pitch angle calculated by the algorithm and the azimuth and pitch angles of the device at this time can be used to calculate the horizontal zero correction value and pitch zero correction value of the device at that location, thereby completing the positioning of the equipment. This method has many problems: First, the finderscope must be adjusted so that the finderscope and telescope are coaxial. Generally, a distant target, such as a building or a tree, is used. The telescope is first adjusted so that the distant target can be observed in the telescope, and then the position of the finderscope is adjusted so that the distant target is imaged in the middle of the finderscope, completing the coaxial adjustment of the telescope and the finderscope. Secondly, when using the finderscope to find stars, if the sun is used for positioning during the day, a Baader film must be installed in front of the finderscope and the front tube of the telescope must be covered. If the star is to be found at night, the operator must first roughly find the star to be located with the naked eye and then use the finderscope to find it. As can be seen from the above description, when using a finderscope for star finding, the degree of automation is not high. Especially for unskilled operators, it takes a long time to complete the above steps. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned deficiencies in the prior art and proposes a high-precision positioning method for a device, in order to simplify the structure of the device, reduce the positioning difficulty of the device, and thus improve the positioning accuracy of the device and the convenience of operation of the device.

[0005] In order to achieve the above-mentioned object, the present invention adopts the following technical solutions:

[0006] The present invention provides a high-precision positioning method for an astronomical device. The astronomical device comprises a telescope mounted on a two-dimensional turntable, an automatic focusing mechanism mounted on the rear end of the telescope, a CCD camera mounted on the rear end of the automatic focusing mechanism, and an electronic compass mounted above the CCD camera. The method is characterized in that the high-precision positioning method is performed according to the following steps:

[0007] Step 1: Let α be the current pitch angle reading of the electronic compass, let β be the current north reading of the electronic compass, let γ represent the comprehensive field of view angle in the horizontal direction after the CCD camera is connected to the telescope, and let δ represent the comprehensive field of view angle in the pitch direction after the CCD camera is connected to the telescope; let the movement adjustment angle be τ; let the horizontal motor in the two-dimensional turntable move in a positive direction with an increasing angle and a negative direction with a decreasing angle;

[0008] Let n be the current number of moves of the two-dimensional turntable, and let N be the maximum number of moves;

[0009] Let flag flag_n indicate whether the two-dimensional turntable performs the nth movement during scanning. If so, let flagn=0; otherwise, let flagn=1;

[0010] Let the flag beacon indicate whether there is a star image on the target surface of the CCD camera. If yes, let beacon=1; otherwise, let beacon=0;

[0011] Step 2: Initialize n=1, set flag_n to 0, and set flag beacon to 0;

[0012] Step 3: Determine the value of α. If α=0, proceed to step 4. Otherwise, move the motor in the pitch direction of the two-dimensional turntable until α=0, and then proceed to step 4.

[0013] Step 4: Determine the value of β. If β=0, proceed to step 5. Otherwise, move the motor in the horizontal direction of the two-dimensional turntable until β=0, and then proceed to step 5.

[0014] Step 5: Select a star in the star map as the target star, and calculate the observed position of the target star at each interval T, so that the two-dimensional turntable rotates to the observed position of the target star at the current interval until the two-dimensional turntable receives a stop tracking command;

[0015] Step 6: Use the CCD camera to collect and analyze images of the area where the observation position is located at the current interval time. If there is no image of the target star in the target surface of the CCD camera, execute step 8; otherwise, execute step 7;

[0016] Step 7: Move the autofocus base until the image quality of the target star on the CCD camera target surface is optimal, thereby calculating the angles from the center of mass of the target star image at the current interval to the center of the CCD camera target surface: θ1 in the horizontal direction and θ2 in the pitch direction; then jump to step 11;

[0017] Step 8: If beacon=1, go to step 11; otherwise, go to step 9;

[0018] Step 9: With the current field of view of the CCD camera as the center, rotate the two-dimensional turntable according to the set scanning path to perform the n-th clockwise or counterclockwise scanning of the area near the center of the field of view:

[0019] When the direction of the motor in the pitch direction of the two-dimensional turntable during the n-th movement is downward, the angle of movement of the motor in the pitch direction of the two-dimensional turntable at the current position is -δ+τ, and step 10 is executed;

[0020] When the direction of the motor in the pitch direction of the two-dimensional turntable during the n-th movement is upward, the angle of movement of the motor in the pitch direction of the two-dimensional turntable at the current position is δ-τ, and step 10 is executed;

[0021] When the direction of the horizontal motor in the two-dimensional turntable during the n-th movement is positive, the angle moved by the horizontal motor in the two-dimensional turntable at the current position is γ-τ, and step 10 is executed;

[0022] When the direction of the horizontal motor in the two-dimensional turntable during the n-th movement is negative, the angle of movement of the horizontal motor in the two-dimensional turntable at the current position is -γ+τ, and step 10 is executed;

[0023] Step 10: Determine whether the CCD camera has star imaging:

[0024] If the target star is imaged in the CCD camera during the current interval, set beacon = 1 and return to step 7 for execution;

[0025] If no target star is imaged in the CCD camera during the current interval, set flag_n=1. If n+1≤N, assign n+1 to n and execute step 9. If n+1>N, the two-dimensional turntable stops rotating and the scan is completed.

[0026] Step 11. Read the current horizontal angle value of the two-dimensional turntable as θ3 and the pitch angle value as θ4. At the same time, calculate the horizontal angle value as θ5 and the pitch angle value as θ6 of the observation position of the target star at the current interval time. Calculate the horizontal zero position of the two-dimensional turntable at the current position as θ1+θ3-θ5 and the pitch zero position as θ2+θ4-θ6, thereby adjusting the angle of the two-dimensional turntable to achieve high-precision positioning.

[0027] The electronic device of the present invention includes a memory and a processor, and is characterized in that the memory is used to store a program that supports the processor to execute the high-precision positioning method, and the processor is configured to execute the program stored in the memory.

[0028] The present invention provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program executes the steps of the high-precision positioning method when executed by a processor.

[0029] Compared with the existing methods, the present invention has the following beneficial effects:

[0030] 1. The present invention combines a turntable telescope system with a CCD camera and an electronic compass. By scanning the turntable and using the CCD camera to obtain star images and perform computational processing on the images, it overcomes the errors caused by traditional methods of using a finderscope for star finding, thereby improving the positioning accuracy of the device.

[0031] 2. The present invention eliminates the finderscope structure above the telescope, simplifies the structure of the entire device, overcomes the need for operators to perform visual coaxial calibration and star-finding operations in the prior art, and reduces the complexity of the positioning process;

[0032] 3. The present invention adopts a fully automated star-finding and positioning method. The entire process is automatic, which improves the degree of automation of the device. The method is simple and convenient to operate and can complete the positioning of the device without excessive human intervention.

[0033] 4. The present invention can plan the scanning and star-seeking area according to specific actual needs to meet different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the present invention;

[0035] Figure 2Visual star map used in the present invention;

[0036] Figure 3 Scanning flow chart for the present invention;

[0037] Figure 4 It is the structural work flow chart of the present invention;

[0038] Numbers in the figure: 1. Two-dimensional turntable; 2. Telescope; 3. Automatic focusing seat; 4. CCD camera; 5. Electronic compass. DETAILED DESCRIPTION

[0039] In this embodiment, Figure 1 As shown, a high-precision positioning method for a device is to set up a telescope 2 on a two-dimensional turntable 1. The two-dimensional turntable 1 uses a direct-drive torque motor with a high-precision absolute circular grating encoder, which has the advantages of high positioning accuracy, fast response, and strong environmental adaptability. An automatic focusing seat 3 is connected to the rear of the telescope 2, and a CCD camera 4 is connected to the rear end of the automatic focusing seat. The forward and backward movement of the automatic focusing seat 3 drives the forward and backward movement of the CCD camera 4, thereby adjusting the imaging clarity of the target surface of the CCD camera 4. An electronic compass 5 is fixed above the CCD camera 4. The electronic compass 5 provides three parameters: heading, pitch, and roll. In this embodiment, the pitch positioning accuracy of the electronic compass 5 is 0.1°, and the heading accuracy is 0.25°. The electronic compass 5 guides the rotation of the two-dimensional turntable 1 so that the horizontal and pitch directions of the telescope 2 are both at 0°.

[0040] In this embodiment, Figure 2 The following is a visual star map, which allows you to view the positions of stars that can be observed at the current position and updates the star positions at an inherent frequency. It specifically includes information such as the star's azimuth, altitude, and brightness, making it easier to select target stars during positioning.

[0041] In this embodiment, Figure 3 The figure shows a simplified diagram of the two-dimensional turntable 1 scanning and searching for stars. Area 1 is the original field of view of the CCD camera 4. With this field of view as the center, the field of view of the CCD camera 4 can be expanded by moving the two-dimensional turntable 1 clockwise.

[0042] In this embodiment, Figure 4 As shown, the high-precision positioning method of the device is carried out in the following steps:

[0043] Step 1. Record the reading of the electronic compass 5, using α to represent the pitch angle reading of the electronic compass 5, and β to represent the horizontal angle reading of the electronic compass 5, and α and β are updated at a fixed frequency. Use γ to represent the size of the integrated field of view in the horizontal direction after the CCD camera 4 is connected to the telescope 2, and use δ to represent the size of the integrated field of view in the pitch direction after the CCD camera 4 is connected to the telescope 2. γ and δ are obtained by combining the parameters of the telescope 2 and the specific CCD camera 4. Through experiments, it is found that the value of γ in this example is about 0.2°, and the value of δ is about 0.17°; let the movement adjustment angle be τ, which is the angle adjustment amount of the two-dimensional turntable 1 during scanning; let the horizontal motor of the two-dimensional turntable 1 move, the direction in which the angle increases is positive, and the direction in which the angle decreases is negative;

[0044] Let n be the current number of moves of the two-dimensional turntable 1. The area where the current field of view is located can be obtained from the actual planned route. Let N be the maximum number of moves of the actual planned scanning route;

[0045] Let flag flag_n indicate that the two-dimensional turntable 1 needs to move for the nth time during scanning. If so, let flag_n=0, otherwise, let flag_n=1;

[0046] Let the flag beacon indicate whether there is a star image on the target surface of the CCD camera 4. If yes, let beacon=1; otherwise, let beacon=0.

[0047] Step 2: Initialize the flags, set n=1, set flag_n=0, and set beacon=0;

[0048] Step 3: To ensure that stars appear in the field of view of the CCD camera 4 during the scanning process, the initial positioning accuracy of the device needs to be guaranteed as much as possible. The electronic compass 5 is used to perform preliminary positioning of the device and determine the value of α. If α = 0, it means that the current pitch direction of the telescope 2 is at the horizontal zero position, and step 4 is executed; otherwise, it means that the current pitch direction of the telescope 2 is not at the horizontal zero position, and the pitch direction motor of the two-dimensional turntable 1 needs to be moved until α = 0, and then step 4 is executed;

[0049] Step 4: Similarly, determine the value of β. If β = 0, proceed to step 5; otherwise, move the horizontal direction motor of the two-dimensional turntable 1 until β = 0 and then proceed to step 5;

[0050] Step 5. Select an observable star in the star map as the target star. The observation position of the target star, i.e., the azimuth and elevation angles of the star observation, are calculated by the star catalog algorithm in combination with the local longitude and latitude, time information, etc. The North Star is generally selected as the target star. The North Star has a small movement angle and can be regarded as an approximately stationary star. The horizontal angle and elevation angle values of the target star at the current time are calculated at intervals of T seconds, and the two-dimensional turntable 1 is controlled to rotate to this position. This process continues until the two-dimensional turntable 1 receives the command to stop tracking the star;

[0051] Step 6: Analyze the image captured by the CCD camera 4. If no star is imaged in the CCD camera 4, proceed to step 8; otherwise, proceed to step 7.

[0052] Step 7: Move the autofocus base 3. The forward and backward movement of the focus base drives the camera to move forward and backward, thereby changing the image quality of the CCD camera 4 target surface. When the image quality of the stars on the target surface of the CCD camera 4 is the best, calculate the correction values in the horizontal and pitch directions. In this example, the experiment uses the telescope 1 and the CCD camera 4 to image a point light source. After rotating the fixed angle value Δθ, the corresponding position of the center of mass of the CCD camera 4 before and after imaging is calculated as m pixels. The angle corresponding to each pixel is obtained as follows: By calculating the difference between the coordinates of the centroid of the star image and the center of the field of view of CCD camera 4, the horizontal correction angle is θ1 and the pitch correction angle is θ2;

[0053] Step 8: If beacon=1, go to step 11; otherwise, go to step 9;

[0054] Step 9: With the current field of view of the CCD camera 4 as the center, rotate the two-dimensional turntable 1 to scan the area near the center of the field of view clockwise or counterclockwise for the nth time:

[0055] When the direction of the motor in the pitch direction of the two-dimensional turntable 1 during the n-th movement is downward, the angle of movement of the motor in the pitch direction of the two-dimensional turntable 1 at the current position is -δ+τ, and step 10 is executed;

[0056] When the direction of the motor in the pitch direction of the two-dimensional turntable 1 during the n-th movement is upward, the angle moved by the motor in the pitch direction of the two-dimensional turntable 1 at the current position is δ-τ, and step 10 is executed;

[0057] When the direction of the horizontal motor in the two-dimensional turntable 1 during the n-th movement is positive, the angle moved by the horizontal motor in the two-dimensional turntable 1 at the current position is γ-τ, and step 10 is executed;

[0058] When the direction of the horizontal motor in the two-dimensional turntable 1 during the n-th movement is negative, the angle moved by the horizontal motor in the two-dimensional turntable 1 at the current position is -γ+τ, and step 10 is executed;

[0059] Step 10: Determine whether the CCD camera 4 has star imaging:

[0060] If the target star is imaged in CCD camera 4, it indicates that the star has been scanned and acquired, and beacon is set to 1, and the process returns to step 7.

[0061] If there is no target star imaged in the CCD camera 4, set flag_n=1. If n+1≤N, assign n+1 to n and execute step 9. If n+1>N, the two-dimensional turntable 1 stops rotating and the scan is completed.

[0062] Step 11, read the horizontal angle value of the two-dimensional turntable 1 at this time as θ3, and the pitch angle value as θ4. θ3 and θ4 are the angle feedback values of the internal circular grating encoder in the horizontal and pitch directions of the two-dimensional turntable 1 at this time. The horizontal observation angle of the target star at this time is obtained by combining the star table with the algorithm as θ5, and the pitch observation angle is θ6. Thus, the horizontal zero position of the two-dimensional turntable 1 at the current position is calculated to be θ1+θ3-θ5, and the pitch direction correction value is θ2+θ4-θ6. Thus, the angle of the two-dimensional turntable (1) is adjusted to achieve high-precision positioning.

[0063] When the star map algorithm is used to calculate that the horizontal angle of a star at this moment is σ1 and the pitch angle is σ2, the horizontal motor of the two-dimensional turntable 1 needs to be rotated to σ1+θ1+θ3-θ5, and the pitch motor of the two-dimensional turntable 1 needs to be rotated to σ2+θ2+θ4-θ6 to make the star located in the center of the telescope field of view.

[0064] In this embodiment, an electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0065] In this embodiment, a computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are executed.

Claims

1. A positioning method for an astronomical device, wherein the astronomical device comprises a telescope (2) mounted on a two-dimensional turntable (1), an automatic focusing base (3) mounted at the rear end of the telescope (2), a CCD camera (4) mounted at the rear end of the automatic focusing base (3), and an electronic compass (5) mounted above the CCD camera (4); characterized in that: The positioning method is carried out in the following steps: Step 1: is the current pitch angle reading of the electronic compass (5), let is the current north reading of the electronic compass (5), let γ represent the comprehensive field angle in the horizontal direction after the CCD camera (4) is connected to the telescope (2), and let δ represent the comprehensive field angle in the pitch direction after the CCD camera (4) is connected to the telescope (2); Let the movement adjustment angle be τ; when the horizontal motor in the two-dimensional turntable (1) moves, the direction in which the angle increases is the positive direction, and the direction in which the angle decreases is the negative direction; make is the current number of moves of the two-dimensional turntable (1), and N is the maximum number of moves; Order Sign Indicates whether the two-dimensional turntable (1) performs the nth movement during scanning. If so, let Otherwise, let ; Let the flag beacon indicate whether there is a star image on the target surface of the CCD camera (4). If yes, let Otherwise, let ; Step 2: Initialization , order mark 0, the beacon flag is 0; Step 3: Judgment If the value of , then proceed to step 4; Otherwise, move the motor of the two-dimensional turntable (1) in the pitch direction until Then, proceed to step 4; Step 4: Judgment If the value of , then execute step 5; otherwise, move the motor of the two-dimensional turntable (1) in the horizontal direction until Then, proceed to step 5; Step 5: Select a star in the star map as the target star, and calculate the observation position of the target star at each interval T, so that the two-dimensional turntable (1) rotates to the observation position of the target star at the current interval until the two-dimensional turntable (1) receives a stop star tracking instruction; Step 6: using the CCD camera (4) to collect and analyze images of the area where the observation position is located at the current interval time; if there is no image of the target star in the target surface of the CCD camera (4), then executing step 8; otherwise, executing step 7; Step 7, move the automatic focusing base (3) until the imaging quality of the target star in the target surface of the CCD camera (4) is optimal, thereby calculating the angles from the center of mass of the target star image at the current interval time to the center of the target surface of the CCD camera (4): , the pitch direction is ; Then jump to step 11; Step 8: If beacon=1, go to step 11; Otherwise, go to step 9; Step 9: With the current field of view of the CCD camera (4) as the center, rotate the two-dimensional turntable (1) according to the set scanning path to perform a clockwise or counterclockwise movement scan on the area near the center of the field of view for the nth time: When the direction of the motor in the pitch direction of the two-dimensional turntable (1) is downward during the n-th movement, the angle of movement of the motor in the pitch direction of the two-dimensional turntable (1) at the current position is , and proceed to step 10; When the direction of the motor in the pitch direction of the two-dimensional turntable (1) is upward during the n-th movement, the angle of movement of the motor in the pitch direction of the two-dimensional turntable (1) at the current position is , and proceed to step 10; When the direction of the horizontal motor in the two-dimensional turntable (1) during the n-th movement is positive, the angle of movement of the horizontal motor in the two-dimensional turntable (1) at the current position is , and proceed to step 10; When the direction of the horizontal motor in the two-dimensional turntable (1) is negative at the nth movement, the angle of movement of the horizontal motor in the two-dimensional turntable (1) at the current position is , and proceed to step 10; Step 10: Determine whether the CCD camera (4) has star imaging: If the target star is imaged in the CCD camera (4) at the current interval, set beacon=1 and return to step 7 for execution; If there is no target star imaged in the CCD camera (4) at the current interval, set flag_n=1. , then, after assigning n+1 to n, execute step 9. If , the two-dimensional turntable (1) stops rotating and the scanning is completed; Step 11: Read the current horizontal angle value of the two-dimensional turntable (1) , the pitch angle value is At the same time, the horizontal angle value of the target star's observation position at the current interval is calculated as , the pitch angle value is , calculate the horizontal zero position of the two-dimensional turntable (1) at the current position as , the zero position in the pitch direction is , thereby adjusting the angle of the two-dimensional turntable (1) to achieve positioning.

2. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the positioning method according to claim 1, and the processor is configured to execute the program stored in the memory.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the positioning method according to claim 1 are executed.

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