Transmission-type anti-vibration controllable path atmospheric turbulence measuring device and method

Abstract

The invention discloses a transmission-type anti-vibration controllable path atmospheric turbulence measuring device, which comprises a laser emission and beam splitting module, and a subsequent light path module, a photoelectric detector and a data acquisition and processing module which are sequentially arranged along the light path direction of the laser emission and beam splitting module, the data acquisition and processing module comprises an AD converter, a data acquisition card and a computer which are connected in sequence, the AD converter is located on one side close to a photoelectric detector, and the photoelectric detector is an enhanced CCD camera or an electron multiplication CCD camera; the method does not need to depend on laser beacons and backward scattering, an active transmission-type differential light path with transmitting end homologous parallel double beams and a receiving end cooperatively regulated and controlled is constructed, common-mode noise such as telescope tracking errors and platform jittering is actively counteracted from the hardware level, double-beam transmission light is directly received, the signal-to-noise ratio is high, and by combining narrow-band filtering and polarization suppression, the detection precision is high. Environmental stray light can be effectively stripped, and light spot centroid positioning and light intensity fluctuation calculation are more accurate.

Description

Technical Field

[0001] This invention belongs to the field of optical measurement instrument technology, and relates to a transmission-type vibration-resistant controllable path atmospheric turbulence measurement device. This invention also relates to a transmission-type vibration-resistant controllable path atmospheric turbulence measurement method. Background Technology

[0002] During atmospheric transmission, laser light is affected by random fluctuations in refractive index caused by turbulence, resulting in a series of effects such as intensity scintillation, angle of arrival fluctuations, beam spreading, and drift. These effects severely limit the performance of high-resolution remote sensing, laser communication, and other systems. Therefore, achieving accurate measurement of atmospheric turbulence intensity is crucial. Accurate and high temporal resolution monitoring has significant scientific research and engineering application value.

[0003] Traditional optical turbulence measurement methods are susceptible to various environmental disturbances such as environmental vibration and platform tilting. These factors introduce non-turbulent beam deflection and light intensity fluctuations at the receiver. Since such interference signals are superimposed on the real turbulence effect signals in the time and frequency domains, the measurement principle based on single-spot absolute motion analysis is difficult to effectively separate them, resulting in limited inversion accuracy.

[0004] To suppress common-mode noise such as platform vibration, the Differential Image Motion Method (DIMM) has been introduced into the field of atmospheric turbulence detection. This method effectively cancels common-mode interference and improves measurement reliability by analyzing the motion difference between image points on two adjacent sub-apertures. However, existing measurement devices based on the differential image motion principle (such as DIMM lidar systems and off-axis reflective optical laser beacon atmospheric turbulence profile measurement devices) still have significant limitations: they either rely on measurement beacons or are susceptible to common-mode noise interference; their measurement paths are usually fixed and lack flexibility; at the same time, the system structure is complex and the optical path adjustment accuracy requirements are high, resulting in high costs, making them unsuitable for vibration-sensitive applications that require lightweight equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, which solves the problem in the prior art where the received beam has an additional spot centroid deviation due to interference from external vibration and the mechanical jitter of the system itself.

[0006] The second objective of this invention is to provide a transmission-based, vibration-resistant, controllable path method for measuring atmospheric turbulence.

[0007] The first technical solution adopted in this invention is a transmission-type anti-vibration controllable path atmospheric turbulence measurement device, including a laser emission and beam splitting module. A subsequent optical path module, a photodetector, and a data acquisition and processing module are arranged sequentially along the optical path direction of the laser emission and beam splitting module. The data acquisition and processing module includes an AD converter, a data acquisition card, and a computer connected in sequence. The AD converter is located on the side closer to the photodetector. The photodetector is an enhanced CCD camera or an electron multiplication CCD camera.

[0008] The first technical solution of this invention is also characterized by: The laser emission and beam splitting module includes a laser, a laser beam expander and a semi-transparent and semi-reflective beam splitter arranged sequentially along the laser's optical path, and a first reflector arranged along the direction of the reflected light from the semi-transparent and semi-reflective beam splitter.

[0009] The laser emission and beam splitting module includes a laser, a semi-transparent and semi-reflective beam splitter and a first transmitting telescope arranged sequentially along the laser's optical path, a first reflecting mirror arranged along the direction of the reflected light from the semi-transparent and semi-reflective beam splitter, and a second transmitting telescope arranged along the direction of the reflected light from the first reflecting mirror.

[0010] The subsequent optical path module includes a first convex lens and a second reflecting mirror arranged sequentially along the direction of the transmitted light path. The subsequent optical path module also includes a second convex lens and a third reflecting mirror arranged sequentially along the direction of the reflected light path. A triangular prism is arranged between the second and third reflecting mirrors, with the two right-angled sides of the triangular prism facing the second and third reflecting mirrors respectively. A third convex lens, a narrowband filter, and an optical wedge are arranged sequentially along the direction of the triangular prism's optical path, or a narrowband filter and a curved optical wedge are arranged sequentially along the direction of the triangular prism's optical path.

[0011] The follow-up optical path module includes a first receiving telescope and a second reflecting mirror arranged sequentially along the direction of the transmitted light path. The follow-up optical path module also includes a second receiving telescope and a third reflecting mirror arranged sequentially along the direction of the reflected light path. A triangular prism is arranged between the second and third reflecting mirrors, with the two right-angled sides of the triangular prism facing the second and third reflecting mirrors respectively. A narrow-band filter and an optical wedge are arranged sequentially along the optical path of the triangular prism.

[0012] The second technical solution adopted in this invention is a transmission-type vibration-resistant controllable path atmospheric turbulence measurement method, comprising the following steps: Step 1: The laser emission and beam splitting module emits two near-plane waves into the atmospheric turbulence. After passing through the atmospheric turbulence, the plane waves are received by the subsequent optical path module and sent to the guiding photodetector to form a dual-spot image. The photodetector converts the spot light signal into an electrical signal. The electrical signal is converted into a digital signal by the data acquisition and processing module to calculate the centroid coordinates and light intensity of the dual spot. Step 2: Calculate the variance of the difference angle of arrival; Step 3: Calculate the variance of light intensity fluctuations; Step 4: Perform atmospheric turbulence intensity inversion.

[0013] The second technical solution of the present invention is further characterized by: Step 1 is performed as follows: Step 1.1: When the laser is not turned on, the background light intensity of the imaging area is collected and used as the background noise reference. When the laser is turned on, the laser emitted from the laser is split into transmitted light and reflected light by a semi-transparent and semi-reflective beam splitter. The transmitted light is directly incident on the atmospheric turbulence as the first optical path, and the reflected light is reflected by a mirror as the second optical path and is parallel to the first optical path and incident on the atmospheric turbulence. Step 1.2: After being transmitted through atmospheric turbulence, the transmitted light is absorbed by the first convex lens or the first receiving telescope and then reflected by the second reflecting mirror. After being transmitted through atmospheric turbulence, the reflected light is absorbed by the second convex lens or the second receiving telescope and then reflected by the third reflecting mirror. The transmitted light and the reflected light converge to one right-angled side of the triangular prism to form two beams. The two beams form two light spots on the imaging surface of the photodetector. Step 1.3: The photodetector converts the light spot signal into an electrical signal containing two-dimensional light intensity distribution and pixel position information. This signal is then converted into a digital signal by an AD converter and transmitted to the computer by the data acquisition card. Finally, a two-dimensional digital image containing two light spots is obtained. Background noise is deducted from the light intensity values ​​of each pixel in the two-dimensional digital image. The computer performs noise suppression processing on the two-dimensional digital image, removing isolated dark noise pixels and isolated bright noise pixels, to obtain a light intensity image containing only the true light intensity distribution of the two light spots. Step 1.4: By setting a coordinate threshold using a computer, the light intensity image is divided into two independent sub-regions, each corresponding to the effective imaging range of the two light spots; Step 1.5, calculate the total light intensity of a single spot in each sub-region:

[0014] in, Representing the first and second subregions respectively i The total light intensity of each light spot m , n These represent the row and column numbers of pixels in the light spot image, respectively. For the first m line, number n Light intensity value at column pixel, This involves the cumulative calculation of the corresponding parameters of all pixels within the selected effective area of ​​the light spot; Step 1.6: Calculate the centroid coordinates for each light spot sub-region:

[0015] in, Representing the first subregion within subregion one i A spot of light in x direction, y The centroid coordinates of the direction, Representing the first subregion within subregion two i A spot of light in x direction, y The centroid coordinates of the direction, i For the first i frame, M , N These represent the total number of pixels in the row and column directions of the selected effective area of ​​the light spot, respectively. For the first m line, number n The coordinates of a column pixel in the image coordinate system.

[0016] Step 2 is performed as follows: Step 2.1, calculate the first... i Differential angle of arrival corresponding to the frame image :

[0017]

[0018] in, For the first i The distance between the centroids of the two light spots in the frame image. f To receive the lens focal length, all data collected by the detector during the specified time period is processed. N The differential angle of arrival sequence is obtained by calculating the angles of arrival for each frame of the image. ; Step 2.2, calculate the variance of the difference angle of arrival:

[0019] in, The variance of the undulation at the difference of arrival angle is the desired value. Sum of squares of centroid spacing for all frames of dual-spot images The mean, The mean of the centroid spacing of all frames of dual-spot images. The square of.

[0020] Step 3 is performed as follows: Step 3.1: Calculate the average light intensity of the two light spots frame by frame. :

[0021] Step 3.2: Calculate the average light intensity of all frames with dual light spots. :

[0022] Step 3.3, calculate the variance of light intensity fluctuations. :

[0023] in, Let V be the variance of light intensity fluctuations. The average light intensity of each frame of dual light spots, This represents the average light intensity of the dual-spot across all frames.

[0024] Step 4 is performed as follows: Step 4.1, under the assumption of uniform atmospheric turbulence distribution along the beam propagation path, for the plane wave propagation model:

[0025] in, D The diameter of the pupil. d Interpupillary distance, L The path length of the light beam in the turbulent medium. The path obtained by using the difference of arrival angle fluctuation variance L Mid-atmospheric turbulence intensity; Step 4.2, calculate the logarithmic amplitude fluctuation variance:

[0026] in, , λ The wavelength of the laser; determine if it is an fluctuation condition: if If it is not a weak fluctuation condition, then the turbulence intensity is... That is the final result; if If the condition is weakly fluctuating, then it is considered a weakly fluctuating condition. Under weakly fluctuating conditions, for the plane wave propagation model:

[0027] in, The path obtained by using the variance of light intensity fluctuations L Mid-atmospheric turbulence intensity; Step 4.3, assuming the atmospheric turbulence intensity sequence retrieved from the variance of the difference arrival angle fluctuation over a certain period of time is: The sequence of atmospheric turbulence intensity derived from the variance of light intensity fluctuations is as follows: ,in, M Let be the number of atmospheric turbulence intensities retrieved during this period. The mean and standard deviation of the two sets of atmospheric turbulence intensity sequences are as follows:

[0028]

[0029] The coefficients of variation for retrieving atmospheric turbulence intensity using the variance of the difference in angle of arrival fluctuation and the variance of light intensity fluctuation are as follows:

[0030] Distribute weights using an inverse weighting method:

[0031] Step 4.4, weighted fusion to obtain the final turbulence intensity:

[0032] The intensity of atmospheric turbulence along the horizontal path is obtained.

[0033] The beneficial effects of this invention are: This invention boasts strong anti-interference capabilities, high measurement accuracy, and eliminates the need for laser beacons and backscattering. By constructing an active transmission differential optical path with co-controlled parallel dual beams at the transmitting end and coordinated control at the receiving end, it actively cancels common-mode noise such as telescope tracking errors and platform jitter at the hardware level. It directly receives the transmitted light from the dual beams, resulting in a high signal-to-noise ratio. Combined with narrowband filtering and polarization suppression, it can effectively remove stray light from the environment, making the centroid positioning of the light spot and the calculation of light intensity fluctuations more accurate, thereby significantly improving the accuracy and reliability of turbulence intensity inversion.

[0034] The device has a simplified structure, low cost and complexity, and significantly better portability in the field: It uses conventional optical components to construct an off-axis optical path, eliminating the bulky structure of complex large-aperture Cassegrain telescopes, multiple sets of off-axis receiving mirrors and high-precision flat panel mirrors. The device is lightweight, easy to assemble and adjust, and has low manufacturing cost. It is especially suitable for field deployment on mobile platforms such as vehicles and airborne platforms, improving the economy and practicality of engineering applications.

[0035] The measurement path is flexible and controllable, breaking through beacon dependence and scene limitations: There is no need to form a laser beacon in the air; by directly adjusting the spacing and angle of the transceiver modules, horizontal, near-horizontal, or oblique measurement paths between urban buildings can be freely set. In contrast, existing reflective devices are limited by beacon positions, mainly performing vertical or oblique profile measurements. Horizontal path applications require complex optical path turning and are easily obstructed. This flexibility allows it to work stably in various complex environments such as densely built-up areas, near-field short-range, and open far-field, widely covering scenarios such as laser communication link monitoring, vehicle-mounted or airborne remote sensing, and near-Earth boundary layer detection.

[0036] The algorithm is stable and reliable, with high data authenticity and superior real-time performance. Based on a plane wave model, it combines differential angle of arrival fluctuation variance, light intensity fluctuation variance, and coefficient of variation, and achieves adaptive fusion through an inverse weighting method to invert atmospheric turbulence intensity. This eliminates the need for complex spherical wave matrix inversion operations required by existing reflective devices. Simultaneously, it features dual-beam synchronous transmission and reception with a sampling frame rate of no less than 100fps, supporting dynamic monitoring of atmospheric turbulence intensity. It can output high temporal resolution monitoring results in real time, significantly improving authenticity and reliability, enhancing security, and exhibiting strong adaptability to near-field measurements. There are no aerial laser beacons, and the laser beam only transmits along the preset measurement path, eliminating the risk of additional laser radiation diffusion. It can be safely applied to urban near-field, vehicle-mounted, or airborne low-altitude detection scenarios.

[0037] Employing a transmission-type differential optical path design, this system effectively suppresses environmental common-mode noise interference, achieves flexible and controllable measurement paths, and significantly simplifies redundant structures, reduces costs and assembly difficulty. Through differential motion variance analysis and light intensity fluctuation variance analysis of dual-spots, and an adaptive inversion algorithm, it can achieve high-precision, anti-interference, and high-time-efficiency monitoring of turbulence intensity. It is particularly suitable for applications that are sensitive to vibration and require lightweight and highly deployable equipment, such as laser communication, remote sensing imaging platforms, and near-Earth atmospheric boundary layer research. It can stably achieve horizontal turbulence detection in complex environments with dense buildings. Attached Figure Description

[0038] Figure 1 This is a structural block diagram of the present invention; Figure 2 This is a flowchart of the present invention; Figure 3 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of the structure of Embodiment 4 of the present invention; Figure 7 This is a schematic diagram of the structure of Embodiment 5 of the present invention; Figure 8 This is a schematic diagram of the structure of Embodiment 6 of the present invention.

[0039] In the diagram, 1. Laser emission and beam splitting module, 11. Laser, 12. Laser beam expander, 13. Semi-transparent and semi-reflective beam splitter, 14. First reflector, 15. First transmitting telescope, 16. Second transmitting telescope, 2. Subsequent optical path module, 21. First convex lens, 22. Second reflector, 23. Second convex lens, 24. Third reflector, 25. Triangular prism, 26. Third convex lens, 27. Narrowband filter, 28. Optical wedge, 29. Curved optical wedge, 210. First receiving telescope, 211. Second receiving telescope, 3. Photodetector, 4. Data acquisition and processing module, 41. AD converter, 42. Data acquisition card, 43. Computer. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0041] Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 1 The system includes a laser emission and beam splitting module 1. Along the optical path of the laser emission and beam splitting module 1, a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4 are arranged in sequence. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side closer to the photodetector 3. The photodetector 3 is an enhanced CCD camera or an electron multiplication CCD camera. The sampling frame rate of the photodetector 3 is not less than 100fps, which is used to capture dynamic dual-spot image sequences. The analog signal output by the photodetector 3, which is related to the centroid position and light intensity of the dual spots, is converted into a digital signal by the AD converter 41, acquired by the data acquisition card 42, and transmitted to the computer 43. Finally, the path atmospheric turbulence intensity is calculated by the inversion algorithm. The photodetector 3 can also be a digital output camera and directly connected to the computer 43 via a data cable.

[0042] The laser emission and beam splitting module 1 is used to generate and split into two near-plane waves; the subsequent optical path module 2 is used to receive the two beams after passing through atmospheric turbulence and to converge and deflect them; the photodetector 3 is used to form two separate light spot images from the received two beams and to convert the optical signal into an electrical signal; the data acquisition and processing module 4 is used to acquire the electrical signal and to calculate the atmospheric turbulence intensity by processing the two light spot images at different times.

[0043] The laser emission and beam splitting module 1 includes a laser 11, a laser beam expander 12 and a semi-transparent beam splitter 13 arranged sequentially along the optical path of the laser 11, and a first reflector 14 arranged along the reflected light direction of the semi-transparent beam splitter 13. The laser beam expander 12 is used to collimate and expand the laser beam into a near-plane wave, the semi-transparent beam splitter 13 is used to split the incident beam into a transmission path and a reflection path, and the first reflector 14 is used to redirect the reflected beam and incident it into atmospheric turbulence.

[0044] The laser emission and beam splitting module 1 includes a laser 11, a semi-transparent and semi-reflective beam splitter 13 and a first transmitting telescope 15 arranged sequentially along the optical path of the laser 11, a first reflecting mirror 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13, and a second transmitting telescope 16 arranged along the reflected light direction of the first reflecting mirror 14. The positions of the semi-transparent and semi-reflective beam splitter 13 and the first reflecting mirror 14 are adjustable to ensure that the two outgoing beams are incident in a parallel manner.

[0045] The subsequent optical path module 2 includes a first convex lens 21 and a second reflecting mirror 22 arranged sequentially along the direction of the transmitted light path. The subsequent optical path module 2 also includes a second convex lens 23 and a third reflecting mirror 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflecting mirror 22 and the third reflecting mirror 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflecting mirror 22 and the third reflecting mirror 24, respectively. A third convex lens 26, a narrow-band filter 27, and an optical wedge 28 are arranged sequentially along the direction of the light path of the triangular prism 25, or a narrow-band filter 27 and a curved optical wedge 29 are arranged sequentially along the direction of the light path of the triangular prism 25. The third convex lens 26 is used to focus the dual beams, the narrow-band filter 27 is used to filter out stray light, and the optical wedge 28 can deflect the two beams of light at a specific angle so that they form two clear light spots with appropriate spacing and separation on the imaging surface of the photodetector 3. The curved optical wedge 29 can combine the deflection function of the optical wedge 28 and the focusing function of the lens.

[0046] The follow-up optical path module 2 includes a first receiving telescope 210 and a second reflecting mirror 22 arranged sequentially along the direction of the transmitted light path. The follow-up optical path module 2 also includes a second receiving telescope 211 and a third reflecting mirror 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflecting mirror 22 and the third reflecting mirror 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflecting mirror 22 and the third reflecting mirror 24, respectively. A narrowband filter 27 and an optical wedge 28 are arranged sequentially along the optical path of the triangular prism 25.

[0047] A transmission-based, vibration-resistant, controllable path method for measuring atmospheric turbulence includes the following steps: Step 1: With laser 11 off, the background light intensity of the imaging area is collected and used as a background noise reference. Laser 11 is then turned on. The laser emitted from laser 11 is split into transmitted and reflected light by a semi-transparent beam splitter 13. The transmitted light, as the first optical path, directly enters the atmospheric turbulence. The reflected light, as the second optical path, is reflected by mirror 14 and then parallel to the first optical path before entering the atmospheric turbulence. The horizontal distance of the atmospheric turbulence is... L In system modeling, it is treated as an isotropic turbulent medium; After being transmitted through atmospheric turbulence, the transmitted light is absorbed by the first convex lens 21 or the first receiving telescope 210 and then reflected by the second reflecting mirror 22. The reflected light after being transmitted through atmospheric turbulence is absorbed by the second convex lens 23 or the second receiving telescope 211 and then reflected by the third reflecting mirror 24. The transmitted light and the reflected light converge to one right-angled side of the triangular prism 25 to reduce the beam spacing and form two beams. The two beams form two light spots on the imaging surface of the photodetector 3. The photodetector 3 converts the light spot signal into an electrical signal containing two-dimensional light intensity distribution and pixel position information. The electrical signal is converted into a digital signal by the AD converter 41 and transmitted to the computer 43 by the data acquisition card 42. Finally, a two-dimensional digital image containing two light spots is obtained as the raw data for centroid calculation. Each pixel in the two-dimensional digital image corresponds to its pixel coordinates. With light intensity value , m , n The row and column numbers of the pixels are respectively. The background noise is removed from the light intensity value of each pixel in the two-dimensional digital image. The computer 43 uses a filtering algorithm (such as median filtering) to perform noise suppression processing on the two-dimensional digital image, removes isolated dark noise pixels and isolated bright noise pixels, and obtains a light intensity image that only contains the true light intensity distribution of the two spots. By setting the coordinate threshold using computer 43, the light intensity image is divided into two independent sub-regions, each corresponding to the effective imaging range of the two light spots; Calculate the total light intensity of a single spot in each sub-region:

[0048] in, Representing the first and second subregions respectively i The total light intensity of each light spot m , n These represent the row and column numbers of pixels in the light spot image, respectively. For the first m line, number n Light intensity value at column pixel, This involves the cumulative calculation of the corresponding parameters of all pixels within the selected effective area of ​​the light spot; Calculate the centroid coordinates for each light spot sub-region:

[0049] in, Representing the first subregion within subregion one i A spot of light in x direction, y The centroid coordinates of the direction, Representing the first subregion within subregion two i A spot of light in x direction, y The centroid coordinates of the direction, i For the first i frame, M , N These represent the total number of pixels in the row and column directions of the selected effective area of ​​the light spot, respectively. For the first m line, number n The coordinates of a column pixel in the image coordinate system.

[0050] Step 2: Calculate the first... i Differential angle of arrival corresponding to the frame image :

[0051]

[0052] in, For the first i The distance between the centroids of the two light spots in the frame image. f To receive the lens focal length, all data collected by the detector during the specified time period is processed. N The differential angle of arrival sequence is obtained by calculating the angles of arrival for each frame of the image. ; Calculate the variance of the difference angle of arrival:

[0053] in, The variance of the undulation at the difference of arrival angle is the desired value. Sum of squares of centroid spacing for all frames of dual-spot images The mean, The mean of the centroid spacing of all frames of dual-spot images. The square of.

[0054] Step 3: Calculate the average light intensity of the two light spots frame by frame. :

[0055] Calculate the average light intensity of the dual-spot across all frames. :

[0056] Calculate the variance of light intensity fluctuations :

[0057] in, Let V be the variance of light intensity fluctuations. The average light intensity of each frame of dual light spots, This represents the average light intensity of the dual-spot across all frames.

[0058] Step 4: Under the assumption of uniform atmospheric turbulence distribution along the beam propagation path, for the plane wave propagation model:

[0059] in, D The diameter of the pupil. d Interpupillary distance, L The path length of the light beam in the turbulent medium. The path obtained by using the difference of arrival angle fluctuation variance L Mid-atmospheric turbulence intensity; Calculate the variance of logarithmic amplitude fluctuations:

[0060] in, , λ The wavelength of the laser; determine if it is an fluctuation condition: if If it is not a weak fluctuation condition, then the turbulence intensity is... That is the final result; if If the condition is weakly fluctuating, then it is considered a weakly fluctuating condition. Under weakly fluctuating conditions, for the plane wave propagation model:

[0061] in, The path obtained by using the variance of light intensity fluctuations L Mid-atmospheric turbulence intensity; Suppose that the atmospheric turbulence intensity sequence obtained by inverting the variance of the difference arrival angle fluctuation over a certain period of time is as follows: The sequence of atmospheric turbulence intensity derived from the variance of light intensity fluctuations is as follows: ,in, M Let be the number of atmospheric turbulence intensities retrieved during this period. The mean and standard deviation of the two sets of atmospheric turbulence intensity sequences are as follows:

[0062]

[0063] The coefficients of variation for retrieving atmospheric turbulence intensity using the variance of the difference in angle of arrival fluctuation and the variance of light intensity fluctuation are as follows:

[0064] Distribute weights using an inverse weighting method:

[0065] The final turbulence intensity is obtained by weighted fusion:

[0066] Based on the inversion results of the atmospheric refractive index structure constant, the intensity of atmospheric turbulence on the horizontal path can be detected, and monitoring data on its time variation can be obtained through continuous detection.

[0067] This invention employs an active, parallel dual-beam splitting structure at the transmitting end for detection, ensuring that both beams propagate along the same turbulent path. At the receiving end, dual-image motion information is acquired synchronously via a dual-beam adaptive optical path. Based on the differential image motion principle and the light intensity scintillation principle, atmospheric turbulence intensity is inverted, effectively suppressing common-mode noise. This enables high-precision, high-temporal-resolution monitoring of atmospheric turbulence intensity along a controllable path, and possesses excellent anti-vibration interference capabilities. This invention significantly improves the accuracy and reliability of measurements through a transmissive differential structure, while also being more compact, reducing costs and assembly difficulty. It offers better portability, operability, and high tracking accuracy, making it particularly suitable for field applications such as laser communication and remote sensing imaging.

[0068] Example 1: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 3 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side close to the photodetector 3. The photodetector 3 is an electron multiplication CCD camera.

[0069] The laser emission and beam splitting module 1 includes a laser 11, a laser beam expander 12 and a semi-transparent and semi-reflective beam splitter 13 arranged sequentially along the optical path of the laser 11, and a first reflector 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13.

[0070] The follower optical path module 2 includes a first convex lens 21 and a second reflector 22 arranged sequentially along the direction of the transmitted light path. The follower optical path module 2 also includes a second convex lens 23 and a third reflector 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflector 22 and the third reflector 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflector 22 and the third reflector 24, respectively. A third convex lens 26, a narrow-band filter 27, and an optical wedge 28 are arranged sequentially along the optical path of the triangular prism 25.

[0071] Example 2: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 4 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side closer to the photodetector 3. The photodetector 3 is an enhanced CCD camera.

[0072] The laser emission and beam splitting module 1 includes a laser 11, a laser beam expander 12 and a semi-transparent and semi-reflective beam splitter 13 arranged sequentially along the optical path of the laser 11, and a first reflector 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13.

[0073] The follower optical path module 2 includes a first convex lens 21 and a second reflector 22 arranged sequentially along the direction of the transmitted light path. The follower optical path module 2 also includes a second convex lens 23 and a third reflector 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflector 22 and the third reflector 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflector 22 and the third reflector 24, respectively. A narrow-band filter 27 and a curved optical wedge 29 are arranged sequentially along the optical path of the triangular prism 25.

[0074] Example 3: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 5 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side close to the photodetector 3. The photodetector 3 is an electron multiplication CCD camera.

[0075] The laser emission and beam splitting module 1 includes a laser 11, a laser beam expander 12 and a semi-transparent and semi-reflective beam splitter 13 arranged sequentially along the optical path of the laser 11, and a first reflector 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13.

[0076] The follow-up optical path module 2 includes a first receiving telescope 210 and a second reflecting mirror 22 arranged sequentially along the direction of the transmitted light path. The follow-up optical path module 2 also includes a second receiving telescope 211 and a third reflecting mirror 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflecting mirror 22 and the third reflecting mirror 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflecting mirror 22 and the third reflecting mirror 24, respectively. A narrowband filter 27 and an optical wedge 28 are arranged sequentially along the optical path of the triangular prism 25.

[0077] Example 4: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 6 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side closer to the photodetector 3. The photodetector 3 is an enhanced CCD camera.

[0078] The laser emission and beam splitting module 1 includes a laser 11, a semi-transparent and semi-reflective beam splitter 13 and a first transmitting telescope 15 arranged sequentially along the optical path of the laser 11, a first reflecting mirror 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13, and a second transmitting telescope 16 arranged along the reflected light direction of the first reflecting mirror 14.

[0079] The follower optical path module 2 includes a first convex lens 21 and a second reflector 22 arranged sequentially along the direction of the transmitted light path. The follower optical path module 2 also includes a second convex lens 23 and a third reflector 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflector 22 and the third reflector 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflector 22 and the third reflector 24, respectively. A third convex lens 26, a narrow-band filter 27, and an optical wedge 28 are arranged sequentially along the optical path of the triangular prism 25.

[0080] Example 5: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 7 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side closer to the photodetector 3. The photodetector 3 is an enhanced CCD camera.

[0081] The laser emission and beam splitting module 1 includes a laser 11, a semi-transparent and semi-reflective beam splitter 13 and a first transmitting telescope 15 arranged sequentially along the optical path of the laser 11, a first reflecting mirror 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13, and a second transmitting telescope 16 arranged along the reflected light direction of the first reflecting mirror 14.

[0082] The follower optical path module 2 includes a first convex lens 21 and a second reflector 22 arranged sequentially along the direction of the transmitted light path. The follower optical path module 2 also includes a second convex lens 23 and a third reflector 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflector 22 and the third reflector 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflector 22 and the third reflector 24, respectively. A narrow-band filter 27 and a curved optical wedge 29 are arranged sequentially along the optical path of the triangular prism 25.

[0083] Example 6: Transmission-type vibration-resistant controllable path atmospheric turbulence measurement device, see [link / reference] Figure 8 It includes a laser emission and beam splitting module 1. Along the optical path direction of the laser emission and beam splitting module 1, there are a subsequent optical path module 2, a photodetector 3, and a data acquisition and processing module 4. The data acquisition and processing module 4 includes an AD converter 41, a data acquisition card 42, and a computer 43 connected in sequence. The AD converter 41 is located on the side close to the photodetector 3. The photodetector 3 is an electron multiplication CCD camera.

[0084] The laser emission and beam splitting module 1 includes a laser 11, a semi-transparent and semi-reflective beam splitter 13 and a first transmitting telescope 15 arranged sequentially along the optical path of the laser 11, a first reflecting mirror 14 arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter 13, and a second transmitting telescope 16 arranged along the reflected light direction of the first reflecting mirror 14.

[0085] The follow-up optical path module 2 includes a first receiving telescope 210 and a second reflecting mirror 22 arranged sequentially along the direction of the transmitted light path. The follow-up optical path module 2 also includes a second receiving telescope 211 and a third reflecting mirror 24 arranged sequentially along the direction of the reflected light path. A triangular prism 25 is arranged between the second reflecting mirror 22 and the third reflecting mirror 24. The two right-angled sides of the triangular prism 25 are opposite to the second reflecting mirror 22 and the third reflecting mirror 24, respectively. A narrowband filter 27 and an optical wedge 28 are arranged sequentially along the optical path of the triangular prism 25.

[0086] Example 7: A transmission-based, vibration-resistant, controllable path method for measuring atmospheric turbulence includes the following steps: Step 1: With the laser 11 off, the background light intensity of the imaging area is collected and used as the background noise reference. The laser 11 is turned on. The laser emitted from the laser 11 is split into transmitted light and reflected light by the semi-transparent and semi-reflective beam splitter 13. The transmitted light is directly incident on the atmospheric turbulence as the first optical path, and the reflected light is reflected by the reflector 14 as the second optical path and is parallel to the first optical path and incident on the atmospheric turbulence. After being transmitted through atmospheric turbulence, the transmitted light is absorbed by the first convex lens 21 or the first receiving telescope 210 and then reflected by the second reflecting mirror 22. After being transmitted through atmospheric turbulence, the reflected light is absorbed by the second convex lens 23 or the second receiving telescope 211 and then reflected by the third reflecting mirror 24. The transmitted light and the reflected light converge to one right-angled side of the triangular prism 25, forming two beams. The two beams form two light spots on the imaging surface of the photodetector 3. The photodetector 3 converts the light spot signal into an electrical signal containing two-dimensional light intensity distribution and pixel position information. The electrical signal is converted into a digital signal by the AD converter 41 and transmitted to the computer 43 by the data acquisition card 42. Finally, a two-dimensional digital image containing two light spots is obtained. The background noise is deducted from the light intensity value of each pixel in the two-dimensional digital image. The computer 43 performs noise suppression processing on the two-dimensional digital image, removes isolated dark noise pixels and isolated bright noise pixels, and obtains a light intensity image containing only the true light intensity distribution of the two light spots. By setting the coordinate threshold using computer 43, the light intensity image is divided into two independent sub-regions, each corresponding to the effective imaging range of the two light spots; Calculate the total light intensity of a single spot in each sub-region:

[0087] in, Representing the first and second subregions respectively i The total light intensity of each light spot m , n These represent the row and column numbers of pixels in the light spot image, respectively. For the first m line, number n Light intensity value at column pixel, This involves the cumulative calculation of the corresponding parameters of all pixels within the selected effective area of ​​the light spot; Calculate the centroid coordinates for each light spot sub-region:

[0088] in, Representing the first subregion within subregion one i A spot of light in x direction, y The centroid coordinates of the direction, Representing the first subregion within subregion twoi A spot of light in x direction, y The centroid coordinates of the direction, i For the first i frame, M , N These represent the total number of pixels in the row and column directions of the selected effective area of ​​the light spot, respectively. For the first m line, number n The coordinates of a column pixel in the image coordinate system.

[0089] Step 2: Calculate the first... i Differential angle of arrival corresponding to the frame image :

[0090]

[0091] in, For the first i The distance between the centroids of the two light spots in the frame image. f To receive the lens focal length, all data collected by the detector during the specified time period is processed. N The differential angle of arrival sequence is obtained by calculating the angles of arrival for each frame of the image. ; Calculate the variance of the difference angle of arrival:

[0092] in, The variance of the undulation at the difference of arrival angle is the desired value. Sum of squares of centroid spacing for all frames of dual-spot images The mean, The mean of the centroid spacing of all frames of dual-spot images. The square of.

[0093] Step 3: Calculate the average light intensity of the two light spots frame by frame. :

[0094] Calculate the average light intensity of the dual-spot across all frames. :

[0095] Calculate the variance of light intensity fluctuations :

[0096] in, Let V be the variance of light intensity fluctuations. The average light intensity of each frame of dual light spots, This represents the average light intensity of the dual-spot across all frames.

[0097] Step 4: Under the assumption of uniform atmospheric turbulence distribution along the beam propagation path, for the plane wave propagation model:

[0098] in, D The diameter of the pupil. d Interpupillary distance, L The path length of the light beam in the turbulent medium. The path obtained by using the difference of arrival angle fluctuation variance L Mid-atmospheric turbulence intensity; Calculate the variance of logarithmic amplitude fluctuations:

[0099] in, , λ The wavelength of the laser; determine if it is an fluctuation condition: if If it is not a weak fluctuation condition, then the turbulence intensity is... That is the final result; if If the condition is weakly fluctuating, then it is considered a weakly fluctuating condition. Under weakly fluctuating conditions, for the plane wave propagation model:

[0100] in, The path obtained by using the variance of light intensity fluctuations L Mid-atmospheric turbulence intensity; Suppose that the atmospheric turbulence intensity sequence obtained by inverting the variance of the difference arrival angle fluctuation over a certain period of time is as follows: The sequence of atmospheric turbulence intensity derived from the variance of light intensity fluctuations is as follows: ,in, M Let be the number of atmospheric turbulence intensities retrieved during this period. The mean and standard deviation of the two sets of atmospheric turbulence intensity sequences are as follows:

[0101]

[0102] The coefficients of variation for retrieving atmospheric turbulence intensity using the variance of the difference in angle of arrival fluctuation and the variance of light intensity fluctuation are as follows:

[0103] Distribute weights using an inverse weighting method:

[0104] The final turbulence intensity is obtained by weighted fusion:

[0105] The intensity of atmospheric turbulence along the horizontal path is obtained.

Claims

1. A transmission-type, vibration-resistant, controllable path atmospheric turbulence measurement device, characterized in that, The system includes a laser emission and beam splitting module (1), and a subsequent optical path module (2), a photodetector (3), and a data acquisition and processing module (4) are arranged sequentially along the optical path direction of the laser emission and beam splitting module (1). The data acquisition and processing module (4) includes an AD converter (41), a data acquisition card (42), and a computer (43) connected in sequence. The AD converter (41) is located on the side close to the photodetector (3). The photodetector (3) is an enhanced CCD camera or an electron multiplication CCD camera.

2. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement device according to claim 1, characterized in that, The laser emission and beam splitting module (1) includes a laser (11), a laser beam expander (12) and a semi-transparent and semi-reflective beam splitter (13) are arranged sequentially along the optical path of the laser (11), and a first reflector (14) is arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter (13).

3. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement device according to claim 1, characterized in that, The laser emission and beam splitting module (1) includes a laser (11), a semi-transparent and semi-reflective beam splitter (13) and a first transmitting telescope (15) arranged sequentially along the optical path of the laser (11), a first reflecting mirror (14) arranged along the reflected light direction of the semi-transparent and semi-reflective beam splitter (13), and a second transmitting telescope (16) arranged along the reflected light direction of the first reflecting mirror (14).

4. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement device according to any one of claims 2 or 3, characterized in that, The subsequent optical path module (2) includes a first convex lens (21) and a second reflector (22) arranged sequentially along the direction of the transmitted light path. The subsequent optical path module (2) also includes a second convex lens (23) and a third reflector (24) arranged sequentially along the direction of the reflected light path. A triangular prism (25) is arranged between the second reflector (22) and the third reflector (24). The two right-angled sides of the triangular prism (25) are opposite to the second reflector (22) and the third reflector (24) respectively. A third convex lens (26), a narrow band filter (27), and an optical wedge (28) are arranged sequentially along the optical path of the triangular prism (25), or a narrow band filter (27) and a curved optical wedge (29) are arranged sequentially along the optical path of the triangular prism (25).

5. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement device according to claim 2 or 3, characterized in that, The follow-up optical path module (2) includes a first receiving telescope (210) and a second reflecting mirror (22) arranged sequentially along the direction of the transmitted light path. The follow-up optical path module (2) also includes a second receiving telescope (211) and a third reflecting mirror (24) arranged sequentially along the direction of the reflected light path. A triangular prism (25) is arranged between the second reflecting mirror (22) and the third reflecting mirror (24). The two right-angled sides of the triangular prism (25) are opposite to the second reflecting mirror (22) and the third reflecting mirror (24) respectively. A narrow-band filter (27) and an optical wedge (28) are arranged sequentially along the optical path of the triangular prism (25).

6. A transmission-based, vibration-resistant, controllable path atmospheric turbulence measurement method, characterized in that, Using the transmission-type vibration-resistant controllable path atmospheric turbulence measurement device as described in claim 4 or 5, the following steps are included: Step 1: The laser emission and beam splitting module (1) emits two near-plane waves into the atmospheric turbulence. After passing through the atmospheric turbulence, the plane waves are received by the follow-up optical path module (2) and sent to the guiding photodetector (3) to form a double spot image. The photodetector (3) converts the spot light signal into an electrical signal. The electrical signal is converted into a digital signal by the data acquisition and processing module (4) to calculate the centroid coordinates and light intensity of the double spot. Step 2: Calculate the variance of the difference angle of arrival; Step 3; Calculate the variance of light intensity fluctuations; Step 4: Perform atmospheric turbulence intensity inversion.

7. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement method according to claim 6, characterized in that, Step 1 is performed as follows: Step 1.1: In the state where the laser (11) is not turned on, the background light intensity of the imaging area is collected and used as the background noise reference. The laser (11) is turned on. The laser emitted from the laser (11) is divided into transmitted light and reflected light by the semi-transparent and semi-reflective beam splitter (13). The transmitted light is directly incident on the atmospheric turbulence as the first optical path. The reflected light is reflected by the reflector (14) as the second optical path and is parallel to the first optical path and incident on the atmospheric turbulence. Step 1.2: After being transmitted through atmospheric turbulence, the transmitted light is absorbed by the first convex lens (21) or the first receiving telescope (210) and then reflected by the second reflecting mirror (22). After being transmitted through atmospheric turbulence, the reflected light is absorbed by the second convex lens (23) or the second receiving telescope (211) and then reflected by the third reflecting mirror (24). The transmitted light and the reflected light converge to one right-angled side of the triangular prism (25) to form two beams. The two beams form two light spots on the imaging surface of the photodetector (3). Step 1.3, the photodetector (3) converts the light spot light signal into an electrical signal containing two-dimensional light intensity distribution and pixel position information. The electrical signal is converted into a digital signal by the AD converter (41) and transmitted to the computer (43) by the data acquisition card (42). Finally, a two-dimensional digital image containing two light spots is obtained. The background noise is deducted from the light intensity value of each pixel in the two-dimensional digital image. The computer (43) performs noise suppression processing on the two-dimensional digital image, removes isolated dark noise pixels and isolated bright noise pixels, and obtains a light intensity image containing only the true light intensity distribution of the two light spots. Step 1.4: The coordinate threshold is set by computer (43) to divide the light intensity image into two independent sub-regions, which correspond to the effective imaging range of the two light spots respectively; Step 1.5, calculate the total light intensity of a single spot in each sub-region: in, Representing the first and second subregions respectively i The total light intensity of each light spot m , n These represent the row and column numbers of pixels in the light spot image, respectively. For the first m line, number n Light intensity value at column pixel, This involves the cumulative calculation of the corresponding parameters of all pixels within the selected effective area of ​​the light spot; Step 1.6: Calculate the centroid coordinates for each light spot sub-region: in, Representing the first subregion within subregion one i A spot of light in x direction, y The centroid coordinates of the direction, Representing the first subregion within subregion two i A spot of light in x direction, y The centroid coordinates of the direction, i For the first i frame, M , N These represent the total number of pixels in the row and column directions of the selected effective area of ​​the light spot, respectively. For the first m line, number n The coordinates of a column pixel in the image coordinate system.

8. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement method according to claim 7, characterized in that, Step 2 is performed as follows: Step 2.1, calculate the first... i Differential angle of arrival corresponding to the frame image : in, For the first i The distance between the centroids of the two light spots in the frame image. f To receive the lens focal length, all data collected by the detector during the specified time period is processed. N The differential angle of arrival sequence is obtained by calculating the angles of arrival for each frame of the image. ; Step 2.2, calculate the variance of the difference angle of arrival: in, The variance of the undulation at the difference of arrival angle is the desired value. Sum of squares of centroid spacing for all frames of dual-spot images The mean, The mean of the centroid spacing of all frames of dual-spot images. The square of.

9. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement method according to claim 8, characterized in that, Step 3 is performed as follows: Step 3.1: Calculate the average light intensity of the two light spots frame by frame. : Step 3.2: Calculate the average light intensity of all frames with dual light spots. : Step 3.3, calculate the variance of light intensity fluctuations. : in, Let V be the variance of light intensity fluctuations. The average light intensity of each frame of dual light spots, This represents the average light intensity of the dual-spot across all frames.

10. The transmission-type vibration-resistant controllable path atmospheric turbulence measurement method according to claim 9, characterized in that, Step 4 is performed as follows: Step 4.1, under the assumption of uniform atmospheric turbulence distribution along the beam propagation path, for the plane wave propagation model: in, D The diameter of the pupil. d Interpupillary distance, L The path length of the light beam in the turbulent medium. The path obtained by using the difference of arrival angle fluctuation variance L Mid-atmospheric turbulence intensity; Step 4.2, calculate the logarithmic amplitude fluctuation variance: in, , λ The wavelength of the laser; determine if it is an fluctuation condition: if If it is not a weak fluctuation condition, then the turbulence intensity is... That is the final result; if If the condition is weakly fluctuating, then it is considered a weakly fluctuating condition. Under weakly fluctuating conditions, for the plane wave propagation model: in, The path obtained by using the variance of light intensity fluctuations L Mid-atmospheric turbulence intensity; Step 4.3, assuming the atmospheric turbulence intensity sequence retrieved from the variance of the difference arrival angle fluctuation over a certain period of time is: The sequence of atmospheric turbulence intensity derived from the variance of light intensity fluctuations is as follows: ,in, M Let be the number of atmospheric turbulence intensities retrieved during this period. The mean and standard deviation of the two sets of atmospheric turbulence intensity sequences are as follows: The coefficients of variation for retrieving atmospheric turbulence intensity using the variance of the difference in angle of arrival fluctuation and the variance of light intensity fluctuation are as follows: Distribute weights using an inverse weighting method: Step 4.4, weighted fusion to obtain the final turbulence intensity: The intensity of atmospheric turbulence along the horizontal path is obtained.

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