Atmospheric coherent length measuring device and measuring method thereof

Abstract

The invention relates to the technical field of atmospheric optical measuring instruments, in particular to an atmospheric coherent length measuring device and a measuring method thereof, and the measuring device comprises a telescope, a focalizer, a primary mirror camera, a star guide mirror, a star guide camera, a PoE power supply communication module, a laser and a computer; the primary mirror camera is connected with the telescope through the focalizer; the focalizer is used for adjusting the focal length of the telescope; the star guide mirror, the PoE power supply communication module and the laser are arranged on the telescope; the star guide camera is connected with the star guide mirror; and the primary mirror camera, the guide star camera, the laser and the computer are all connected with the PoE power supply communication module. The method has the advantages that by adding the focalizer, better and faster focusing work is realized, the telescope obtains clearer fixed star light spot images, and atmospheric coherence length parameters can be calculated more accurately.

Description

Technical Field

[0001] The invention relates to the technical field of atmospheric optical measuring instruments, and in particular to an atmospheric coherence length measuring device and a measuring method thereof. Background Art

[0002] Atmospheric turbulence is an irregular, random, multi-scale flow structure in the atmosphere, caused by the uneven distribution of factors such as temperature, density, and humidity, which leads to irregular changes in the speed and direction of air flow. Atmospheric turbulence can cause random changes in the phase of light waves transmitted in the atmospheric channel, random fluctuations in light intensity, and fluctuations in the angle of arrival, which seriously affects the propagation quality of the light beam in the atmospheric channel. The atmospheric coherence length is a parameter that measures the comprehensive turbulence intensity on the propagation path, and is of great significance in laser communication, astronomical site selection, and other aspects. The atmospheric coherence length instrument is based on the principle of differential image motion, uses starlight as the light source, and calculates the atmospheric coherence length value by measuring the fluctuations in the angle of arrival of starlight arriving at the surface of the CMOS (complementary metal oxide semiconductor) camera. However, the existing atmospheric coherence length measuring instruments have problems such as inconvenient focusing, short focusing distance, and small focusing scale, which results in a long time required to measure star images, which is not conducive to the instrument's star guiding and star tracking work. Summary of the invention

[0003] In view of this, the present invention aims to provide an atmospheric coherence length measuring device and a measuring method thereof, which can increase the focusing distance, reduce the time required for focusing, obtain clearer target star images faster, and enable the equipment to better perform star guiding and tracking work.

[0004] To achieve the above-mentioned purpose, the technical solution created by the present invention is implemented as follows: an atmospheric coherence length measuring device, including a telescope, a focuser, a primary mirror camera, a guide mirror, a guide camera, a PoE power supply communication module, a laser and a computer; the primary mirror camera is connected to the telescope through the focuser; the focuser is used to adjust the focal length of the telescope; the guide mirror, the PoE power supply communication module and the laser are all arranged on the telescope; the guide camera is connected to the guide mirror; the primary mirror camera, the guide camera, the laser and the computer are all connected to the PoE power supply communication module.

[0005] Furthermore, one end of the focuser is connected to the eyepiece end of the telescope, and the other end of the focuser is connected to the imaging end of the primary mirror camera.

[0006] Furthermore, the guide mirror, the PoE power supply communication module and the laser are arranged on the lens barrel of the telescope.

[0007] Furthermore, the imaging end of the guide camera is arranged behind the guide mirror.

[0008] Furthermore, the primary mirror camera, the guide camera, the laser and the computer are respectively connected to the PoE power supply communication module by communication.

[0009] Furthermore, the telescope is arranged on a turntable, and the turntable enables the telescope to move along two directions of freedom.

[0010] Furthermore, the telescope can move along the x-axis direction and the y-axis direction.

[0011] Furthermore, the focusing stroke of the focus adjuster is a first preset value; and the wavelength of the laser is a second preset value.

[0012] Furthermore, the first preset value is 42 mm; the second preset value is 532 nm.

[0013] A method for measuring atmospheric coherence length is implemented using the above-mentioned atmospheric coherence length measuring device, and the specific steps are as follows: S1: Connect the primary mirror camera to the telescope through the focuser, set the guide mirror, PoE power supply communication module and laser on the telescope, and then connect the guide camera to the guide mirror.

[0014] S2: Connect the primary mirror camera, guide camera, laser and computer to the PoE power supply communication module.

[0015] S3: Open the atmospheric coherence length parameter measurement software in the computer, and then start the primary mirror camera, guide camera and laser through the atmospheric coherence length parameter measurement software.

[0016] S4: Adjust the telescope position so that the laser points to the target star; when the target star appears in the image of the guide camera, turn off the laser.

[0017] S5: Observe the target star in the guide camera image and fine-tune the position of the telescope so that the target star is located in the center of the guide camera image.

[0018] S6: Use the focuser to adjust the focus of the telescope so that two clear light spots appear in the primary mirror camera.

[0019] S7: Atmospheric coherence length parameter measurement software detects the coordinate positions of the two light spots.

[0020] S8: The atmospheric coherence length parameter measurement software calculates the atmospheric coherence length according to the coordinate positions of the two light spots and saves the measurement data.

[0021] Compared with the prior art, the invention can achieve the following beneficial effects: 1) By adding a focuser, better and faster focusing can be achieved, the telescope can obtain clearer star spot images, and the atmospheric coherence length parameters can be calculated more accurately.

[0022] 2) Use the guide mirror and guide camera to monitor the telescope’s pointing direction in real time to see if it deviates. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 Schematic diagram of the structure of an atmospheric coherence length measurement device provided according to an embodiment of the present invention.

[0024] The reference numerals include: 1. telescope; 2. focuser; 3. primary mirror camera; 4. guide mirror; 5. guide camera; 6. PoE power supply communication module; 7. laser; 8. computer. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the invention more clear, 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 here are only used to explain the invention and do not constitute a limitation of the invention.

[0026] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying 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 therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0028] 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.

[0029] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0030] like Figure 1 As shown, an atmospheric coherence length measuring device provided by an embodiment of the present invention includes a telescope 1, a focuser 2, a primary mirror camera 3, a guide mirror 4, a guide camera 5, a PoE power supply communication module 6, a laser 7 and a computer 8.

[0031] The primary mirror camera 3 is connected to the telescope 1 through the focuser 2. The focuser 2 is used to adjust the focal length of the telescope 1. The guide mirror 4, the PoE power supply communication module 6 and the laser 7 are arranged on the telescope 1. The guide camera 5 is connected to the guide mirror 4, and the primary mirror camera 3, the guide camera 5, the laser 7 and the computer 8 are all connected to the PoE power supply communication module 6.

[0032] Power over Ethernet (PoE), also known as PoE power supply, is a technology that can transmit power and data to devices through twisted pair cables in Ethernet.

[0033] The PoE power supply communication module 6 is a device that can integrate power and data signals into one network cable for transmission.

[0034] Principle: The PoE power supply communication module 6 mainly includes two parts: the power supply equipment (PSE) and the powered device (PD). The power supply equipment provides DC power to the powered device through the network cable to meet the power demand of the device. While transmitting the data signal, the POE power supply module encapsulates the power signal in the data signal and transmits it to the powered device through the network cable. The powered device extracts the DC power from the network cable and receives the data signal at the same time.

[0035] Furthermore, one end of the focuser 2 is connected to the eyepiece end of the telescope 1 , and the other end of the focuser 2 is connected to the imaging end of the primary mirror camera 3 .

[0036] The guide mirror 4 , the PoE power supply communication module 6 and the laser 7 are all arranged on the lens barrel of the telescope 1 .

[0037] The guide camera 5 is connected to the guide mirror 4, and the imaging end of the guide camera 5 is arranged behind the guide mirror 4. The guide mirror 4 is arranged on the lens barrel of the telescope 1, and is used to monitor the position change of the target star. The front of the guide mirror 4 is the end pointing to the target star, which is responsible for capturing and focusing the light of the target star. The rear of the guide mirror 4 is the end away from the target star, and the guide mirror 4 is responsible for transmitting the position information of the target star to the computer 8 for accurate tracking adjustment.

[0038] The guide mirror 4 can provide a stable reference point for the telescope 1. By capturing the image of the target star through the guide camera 5, it is possible to monitor in real time whether the pointing direction of the telescope 1 is shifted. Once the shift is detected, the computer 8 can be used to control the telescope 1 to correct it, thereby ensuring that the telescope 1 can accurately track the target star.

[0039] Furthermore, the primary mirror camera 3, the guide camera 5, the laser 7 and the computer 8 are respectively connected to the PoE power supply communication module 6 by communication. In this embodiment, the PoE power supply communication module 6 simultaneously supplies power and communicates to the primary mirror camera 3, the guide camera 5, the laser 7 and the computer 8 through a network cable. The primary mirror camera 3, the guide camera 5, the laser 7 and the computer 8 all adopt a structure that supports power transmission and data communication with the PoE power supply communication module 6 through a network cable.

[0040] Furthermore, the telescope 1 is arranged on a turntable, and the telescope can move along two directions of freedom through the turntable. In this embodiment, the telescope 1 can move linearly along the x-axis direction and the y-axis direction.

[0041] Furthermore, the focusing stroke of the focuser 2 is a first preset value, and the wavelength of the laser 7 is a second preset value. The first preset value is 42 mm, and the second preset value is 532 nm.

[0042] In this embodiment, the aperture of the telescope 1 is 280 mm. The resolution of the primary mirror camera 3 is 1920×1200, and the sampling frequency is 100 Hz. The resolution of the guide camera 5 is 2592×1944. The PoE power supply communication module 6 supports POE devices with a voltage range of 12-48V and has four Gigabit network output interfaces. The wavelength of the laser 7 is 532nm and the power is 30mW.

[0043] A method for measuring atmospheric coherence length is implemented using the above-mentioned atmospheric coherence length measuring device, and the specific steps are as follows: S1: Connect the primary mirror camera 3 to the telescope 1 through the focuser 2, set the guide mirror 4, PoE power supply communication module 6 and laser 7 on the telescope 1, and then connect the guide camera 5 to the guide mirror 4.

[0044] One end of the focuser 2 is connected to the eyepiece end of the telescope 1, and the other end of the focuser 2 is connected to the imaging end of the primary mirror camera 3. The guide mirror 4, the PoE power supply communication module 6 and the laser 7 are all arranged on the lens barrel of the telescope 1. The imaging end of the guide camera 5 is arranged behind the guide mirror 4.

[0045] S2: The primary mirror camera 3, the guide camera 5, the laser 7 and the computer 8 are all connected to the PoE power supply communication module 6 by communication.

[0046] S3: Open the atmospheric coherence length parameter measurement software in the computer 8, and then start the primary mirror camera 3, the guide camera 5 and the laser 7 through the atmospheric coherence length parameter measurement software.

[0047] S4: Adjust the position of the telescope 1 so that the laser emitted by the laser 7 points to the target star; when the target star appears in the image of the guide camera 5, turn off the laser 7.

[0048] The telescope 1 is set on a turntable, and a guide mirror 4 is used to provide a reference point for the telescope 1. The turntable is adjusted to adjust the position of the telescope 1 in the x-axis direction and the y-axis direction, so that the laser emitted by the laser 7 points to the target star. When the target star appears in the image of the guide camera 5, the laser 7 is turned off.

[0049] S5: Observe the target star in the image of the guide camera 5, and fine-tune the position of the telescope 1 so that the target star is located at the center of the image of the guide camera 5. At this time, the target star image will appear in the primary mirror camera 3.

[0050] S6: The focal length of the telescope 1 is adjusted by the focuser 2 so that two clear light spots appear in the primary mirror camera 3.

[0051] S7: The atmospheric coherence length parameter measurement software starts to detect the coordinate positions of the two light spots, and based on the coordinate positions of the two light spots, telescope 1 can track the stars.

[0052] The atmospheric coherence length parameter measurement software detects the coordinate positions of the two light spots. First, the binarization threshold of the image is calculated, and the image is binarized. According to the binarization result of the image, the light spots in the image are segmented to determine the positions of the light spots. Then, the grayscale value weighted average calculation is performed on the grayscale image of the light spots according to the positions of the light spots to calculate the centroid coordinates of the light spots.

[0053] S8: The atmospheric coherence length parameter measurement software calculates the atmospheric coherence length according to the coordinate positions of the two light spots and saves the measurement data.

[0054] Atmospheric coherence length is an existing algorithm called differential imaging method (DIMM). The essence of differential imaging method (DIMM) is to detect the fluctuation of arrival angle caused by wavefront distortion. It is reflected in the random jitter of the relative position of two star spots on the image plane at the receiving end. The atmospheric coherence length r0 is obtained by counting the jitter variance of the center of mass of the two star spots. The software calculates the atmospheric coherence length parameter based on this differential imaging method.

[0055] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An atmospheric coherence length measuring device, characterized in that: The invention comprises a telescope, a focuser, a primary mirror camera, a guide mirror, a guide camera, a PoE power supply communication module, a laser and a computer; the primary mirror camera is connected to the telescope through the focuser; the focuser is used to adjust the focal length of the telescope; the guide mirror, the PoE power supply communication module and the laser are all arranged on the telescope; the guide camera is connected to the guide mirror; the primary mirror camera, the guide camera, the laser and the computer are all connected to the PoE power supply communication module.

2. The atmospheric coherence length measuring device according to claim 1, characterized in that: One end of the focuser is connected to the eyepiece end of the telescope, and the other end of the focuser is connected to the imaging end of the primary mirror camera.

3. The atmospheric coherence length measuring device according to claim 1, characterized in that: The guide mirror, the PoE power supply communication module and the laser are arranged on the lens barrel of the telescope.

4. The atmospheric coherence length measuring device according to claim 1, characterized in that: The imaging end of the guide camera is arranged behind the guide mirror.

5. The atmospheric coherence length measuring device according to claim 1, characterized in that: The primary mirror camera, the guide camera, the laser and the computer are respectively connected to the PoE power supply communication module by communication.

6. The atmospheric coherence length measuring device according to claim 1, characterized in that: The telescope is arranged on a turntable, and the turntable enables the telescope to move along two directions of freedom.

7. The atmospheric coherence length measuring device according to claim 6, characterized in that: The telescope can move along the x-axis direction and the y-axis direction.

8. The atmospheric coherence length measuring device according to claim 1, characterized in that: The focusing stroke of the focuser is a first preset value; and the wavelength of the laser is a second preset value.

9. The atmospheric coherence length measuring device according to claim 8, characterized in that: The first preset value is 42 mm; the second preset value is 532 nm.

10. An atmospheric coherence length measurement method, implemented by using the atmospheric coherence length measurement device according to any one of claims 1 to 9, characterized in that: The specific steps are as follows: S1: connecting the primary mirror camera to the telescope through the focuser, placing the guide mirror, the PoE power supply communication module and the laser on the telescope, and then connecting the guide camera to the guide mirror; S2: Connecting the primary mirror camera, the guide camera, the laser and the computer to the PoE power supply communication module; S3: opening the atmospheric coherence length parameter measurement software in the computer, and then starting the primary mirror camera, the guide camera and the laser through the atmospheric coherence length parameter measurement software; S4: adjusting the position of the telescope so that the laser points to the target star; when the target star appears in the image of the guide camera, turning off the laser; S5: observing the target star in the image of the guide camera, and adjusting the position of the telescope so that the target star is located at the center of the image of the guide camera; S6: adjusting the focal length of the telescope by means of the focus adjuster so that two clear light spots appear in the primary mirror camera; S7: the atmospheric coherence length parameter measurement software detects the coordinate positions of the two light spots; S8: The atmospheric coherence length parameter measurement software calculates the atmospheric coherence length according to the coordinate positions of the two light spots and saves the measurement data.

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