An airglow layer gravity wave spectrum temperature imaging system and a two-dimensional temperature field point-surface fusion inversion method

Abstract

The present invention relates to an airglow layer gravity wave spectral temperature imaging system and a two-dimensional temperature field point-surface fusion inversion method, comprising a fine spectrum detection subsystem, a rotational temperature spectrum measurement subsystem, and a large-field-of-view gravity wave imaging subsystem. The three subsystems are each provided with three increasing field-of-view angles and perform synchronous detection. The detection area and the detection target are organically coordinated. Later, through image and data processing, the fine spectrum detection subsystem and the rotational temperature spectrum measurement subsystem are collaboratively calibrated to achieve high-precision inversion of atmospheric temperature and obtain a linear relationship between airglow radiation intensity and atmospheric temperature. Using small, medium, and large field-of-view collaborative observation modes, and through a point-surface fusion detection method and a data inversion algorithm, the highly accurate linear relationship between airglow radiation intensity and atmospheric temperature constructed by single-point detection is expanded and fused to an airglow radiation field with horizontal two-dimensional resolution, thereby obtaining a temperature field with the same horizontal two-dimensional resolution of detection accuracy.

Description

Technical Field

[0001] The present invention relates to the field of near-space atmospheric multi-parameter optical remote sensing detection, and in particular to an airglow layer gravity wave spectrum temperature imaging system and a two-dimensional temperature field point-surface fusion inversion method. Background Art

[0002] Near-space, typically referring to the airspace between 20 and 100 kilometers above sea level, represents a transitional zone between traditional aviation and aerospace. It holds unique strategic value and scientific significance, and its environmental characteristics have become a frontier for multidisciplinary research. Precise detection of atmospheric parameters such as temperature, density, photochemical processes, and dynamic disturbances in this region provides crucial support and assurance for modern communications, environmental monitoring, national defense security, and space operations.

[0003] Passive optical remote sensing remains a key mainstream approach for detecting multiple parameters, such as near-space atmospheric temperature and density. This technique uses near-space airglow radiation (such as O₂ and OH) as a light source. Using optical imaging or photometry, it detects the intensities and ratios of its vibrational and rotational energy level spectra to infer the rotational temperature. Currently, two types of instruments are available. One type, based on the principle of dynamic scanning spectrometers, offers high spectral resolution and a wide wavelength scanning range. However, the presence of a narrow slit limits light throughput, and dynamic scanning reduces temporal resolution, making it difficult to capture short-duration dynamic processes. Furthermore, these instruments are bulky, relatively expensive, and require high vibration resistance. The other type, based on the principle of spectrophotometry, leverages the oblique spectral scanning properties of narrowband interference filters and the imaging capabilities of high-sensitivity CCDs to achieve static spectral detection. While filter switching is required to detect different wavelengths, the high optical throughput allows for high temporal resolution, a simpler design, and a more cost-effective approach. However, these two types of instruments can only detect the average temperature of the atmosphere within a single field of view. They are single-point detections and have certain limitations in practical applications.

[0004] At present, there is another type of instrument that can achieve large-scale imaging detection, namely the airglow all-sky imager, but this type of instrument can only detect the distribution of airglow radiation intensity and does not have the ability to detect temperature. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention proposes an airglow layer gravity wave spectral temperature imaging system and a two-dimensional temperature field point-surface fusion detection method. The rotational spectrum detection technology is coupled with the large-field-of-view imaging technology, a multi-field-of-view collaborative observation mode is designed, and a correlation model between airglow radiation intensity and atmospheric temperature is constructed. Through the point-surface fusion inversion algorithm, the purpose of large-scale, high-temporal and spatial resolution two-dimensional temperature field detection is achieved.

[0006] In order to achieve the above object, the technical solution proposed by the present invention is:

[0007] An airglow layer gravity wave spectrum temperature imaging system includes a fine spectrum detection subsystem, a rotation temperature spectrum measurement subsystem, and a large field of view gravity wave imaging subsystem; the fine spectrum detection subsystem includes a front cylindrical optical lens, an optical slit, a double-cemented positive lens a, a double-cemented positive lens b, a spliced ​​double-step grating, a narrow-band filter a, a double-cemented positive lens c, an imaging lens a, and a scientific-grade CCD camera a, which are sequentially arranged along the incident path of light; light is incident on the spliced ​​double-step grating and is reflected, and the reflected light beam passes through the double-cemented positive lens b, the narrow-band filter a, the double-cemented positive lens c, the imaging lens a, and the scientific-grade CCD camera a. Lens c and imaging lens a enter scientific-grade CCD camera a; the rotational temperature spectrum measurement subsystem includes a light shielding ring group, a field stop a, a telephoto relay lens, a narrow-band filter b, an imaging lens b, and a scientific-grade CCD camera b, which are sequentially arranged along the light incident path; the large-field gravity wave imaging subsystem includes a front optical lens b, a field stop b, a large-aperture doublet lens a, a large-aperture doublet lens b, a large-aperture doublet lens c, a large-aperture doublet lens d, a narrow-band filter c, an imaging lens c, and a scientific-grade CCD camera c, which are sequentially arranged along the light incident path;

[0008] The fine spectrum detection subsystem, rotational temperature spectrum measurement subsystem and large-field-of-view gravity wave imaging subsystem adopt successively increasing field of view angles and conduct coordinated observations; light from the corresponding field of view of the airglow layer is incident on the fine spectrum detection subsystem, forming a fine spectrum image of the airglow within the corresponding field of view of the airglow layer; light from the corresponding field of view of the airglow layer is incident on the rotational temperature spectrum measurement subsystem, forming a characteristic spectrum image of the airglow within the corresponding field of view of the airglow layer; light from the corresponding field of view of the airglow layer is incident on the large-field-of-view gravity wave imaging subsystem, forming a two-dimensional image with spatial resolution of the airglow radiation intensity within the corresponding field of view of the airglow layer; the airglow layer gravity wave spectrum temperature imaging system uses the coordinated inversion of the fine spectrum image of the airglow and the characteristic spectrum image of the airglow to obtain high-precision atmospheric temperature and the linear relationship between the airglow radiation intensity and the atmospheric temperature, and combines the two-dimensional image inversion to convert it into a two-dimensional temperature field with the same resolution.

[0009] A further design of the above technical solution is: the spliced ​​double-step grating is composed of a first step grating and a second step grating, a 1 、 a 2 are the grating constants of the first and second step gratings, m 1. m 2 are the diffraction orders of the first and second step gratings, θ m1 、 θ m2are the diffraction angles of the first and second step gratings, λ 1 、 λ 2 are the wavelengths of the first and second echelle gratings, θ i1 、 θ i2 are the incident angles of the first and second step gratings, θ t is the Littrow angle, then the parameter relationship between the two step gratings in the spliced ​​double step grating satisfies the following formula:

[0010] , ;

[0011] Alternatively, the parameter relationship between the two step gratings in the spliced ​​double step grating satisfies the following formula:

[0012] , ;

[0013] Alternatively, the parameter relationship between the two step gratings in the spliced ​​double step grating satisfies the following formula:

[0014] , .

[0015] The field of view angle of the fine spectrum detection subsystem is about 1.8~2.5°, the field of view angle of the rotational temperature spectrum measurement subsystem is about 8.5~11.5°, and the field of view angle of the large field of view gravity wave imaging subsystem is about 90°~110°.

[0016] The optical slit in the fine spectrum detection subsystem is arranged at the lower focal plane of the front cylindrical optical lens, and is arranged closely to the double-cemented positive lens a, and is arranged at one focal length of the double-cemented positive lens b; the narrowband filter a is arranged on the electric filter wheel a and is located at one focal length of the double-cemented positive lens b. Plane mirrors a and plane mirrors b are provided on both sides of the narrowband filter a. Plane mirror a reflects the bottom-up light beam reflected by the spliced ​​double-step grating into a horizontal light beam, and plane mirror b reflects the horizontal light beam into a vertical light beam.

[0017] The rotational temperature spectrum measurement subsystem is arranged on the light-shielding lens barrel a. The light-shielding ring group is composed of multiple layers of nested anodized aluminum light-shielding rings and is arranged on the top of the light-shielding lens barrel a. The field stop a is arranged close to the lower end of the light-shielding ring group and is located at the front focus of the telephoto relay lens; the narrowband filter b is arranged on the electric filter wheel b located in the middle of the light-shielding lens barrel a, and the housing of the electric filter wheel b is equipped with a TEC precision temperature controller. The scientific-grade CCD camera b is arranged at the bottom end of the light-shielding lens barrel a.

[0018] The large-field-of-view gravitational wave imaging subsystem is disposed on a light-shielding lens barrel b. The front optical lens b is disposed at the top of the light-shielding lens barrel b. The field stop b is closely attached to the bottom of the front optical lens b. The large-aperture doublet lens a and the large-aperture doublet lens b have the same focal length, ranging from 100 mm to 150 mm. The focal plane of the front optical lens b is located at the center of the large-aperture doublet lens a. The large-aperture doublet lens c and the large-aperture doublet lens d have the same focal length, ranging from 300 mm to 400 mm. A narrowband filter c is disposed on a motorized filter wheel c located in the middle of the light-shielding lens barrel b. A scientific-grade CCD camera c is disposed at the bottom of the light-shielding lens barrel b.

[0019] The airglow layer gravity wave spectral temperature imaging system also includes a CNC-machined chassis housing. The fine spectrum detection subsystem, the rotational temperature spectrum measurement subsystem, and the large-field-of-view gravity wave imaging subsystem are arranged in the CNC-machined chassis housing and supported on an optical honeycomb baseplate provided at the bottom of the CNC-machined chassis housing. The top of the CNC-machined chassis housing is provided with three quartz glass sealed optical windows that are precisely aligned with the fields of view of the three subsystems, respectively. The quartz glass sealed optical windows have a light transmittance greater than 92% and are coated with a 300-1100nm anti-reflection film. TEC semiconductor air conditioners a and TEC semiconductor air conditioners b are diagonally arranged on two opposite side walls of the CNC-machined chassis housing. An industrial computer control module is provided below TEC semiconductor air conditioner a on the side wall of the CNC-machined chassis housing, a waterproof aviation plug is provided below the industrial computer control module, and a power module is provided above TEC semiconductor air conditioner b.

[0020] A two-dimensional temperature field point-surface fusion inversion method based on the above-mentioned airglow layer gravity wave spectral temperature imaging system comprises the following steps:

[0021] Step 1: Use the fine spectrum detection subsystem to obtain the fine spectrum image of the airglow, and invert the airglow radiation intensity and atmospheric temperature in the corresponding field of view; use the rotational temperature spectrum measurement subsystem to obtain the airglow characteristic spectrum image, and invert the airglow radiation intensity and atmospheric temperature in the corresponding field of view;

[0022] Step 2: Based on the laboratory's multi-parameter fine calibration, the airglow radiation intensity inverted by the fine spectrum detection subsystem and the rotational temperature spectrum measurement subsystem is calculated through spectral segment fusion, and the airglow radiation intensity calculated after spectral segment fusion is fused with the atmospheric temperature inverted by the two subsystems to eliminate the systematic error and obtain high-precision atmospheric temperature. T , and regression analysis was used to establish the airglow radiation intensity I and atmospheric temperature T The mathematical relationship between IT relation;

[0023] Step 3: Use the large-field gravity wave imaging subsystem to obtain a two-dimensional image and invert the horizontal two-dimensional airglow radiation intensity within the large field of view; based on the laboratory fine calibration, the horizontal two-dimensional airglow radiation intensity is converted into the horizontal two-dimensional airglow radiation intensity within the common spectrum of the three subsystems. I 2D ;

[0024] Step 4: Use the data built in step 2 IT Relationship, the horizontal two-dimensional airglow radiation intensity I 2D Converted into horizontal two-dimensional temperature field T 2D .

[0025] The method for inverting the daylight glow radiation intensity and atmospheric temperature using the fine spectrum image of the airglow obtained by the fine spectrum detection subsystem in step 1 is as follows: denoising and removing background stray light signals from the original daylight glow image data obtained by the fine spectrum detection subsystem to obtain inverted image data; accurately locating and correcting the positions of each spectral line based on laboratory calibration data to obtain original spectrum data; performing fine spectrum extraction on the original spectrum data, first averaging multiple sets of original spectrum data at the highest solar altitude angle on that day to obtain a reference spectrum of the sun and sky background, performing normalization processing, and removing it from the original spectrum data; the remaining spectrum data is then subjected to Ring effect correction, dual-band spectrum splicing, and spectrum secondary positioning correction in sequence to obtain the final daylight glow fine spectrum; and using a multi-line ratio method or a slope method to invert the rotation temperature to obtain the daylight glow rotation temperature.

[0026] The method for inverting the night airglow radiation intensity and atmospheric temperature by using the fine spectrum image of the airglow obtained by the fine spectrum detection subsystem in step 1 is as follows: denoising the original night airglow image data obtained by the fine spectrum detection subsystem; filtering the effective numerical value area of ​​the denoised image data by the received light intensity, and calculating the misalignment correction value of each row of pixels by judging the peak position of the received light intensity in each row of pixels to correct the pincushion distortion introduced by the lens to obtain a fine night airglow spectrum image; performing nonlinear fitting on the fine night airglow spectrum image to eliminate the residual background noise; performing Gaussian fitting on the remaining spectral signal peaks to obtain the final night airglow fine spectrum intensity data; and using the slope method to invert the rotation temperature to obtain the night airglow rotation temperature.

[0027] The method for inverting the airglow radiation intensity and atmospheric temperature using the airglow characteristic spectrum image obtained by the rotational temperature spectrum measurement subsystem in step 1 adopts a multi-parameter adaptive iterative inversion algorithm, which compares and calculates the synthetic spectrum of the standard reference at different temperatures in the forward simulation with the synthetic spectrum of the actual observation, and calculates the minimum average difference between the two to determine the actual observed temperature; the synthetic spectrum of the standard reference is simulated by a forward model, and the forward model includes an airglow radiation spectrum, atmospheric radiation transmission, an optical system submodule and a CCD sensor module, and the airglow radiation spectrum, atmospheric radiation transmission and optical system submodule simulate the airglow radiation intensity received by the rotational temperature spectrum measurement subsystem, and then the CCD sensor module performs photoelectric conversion and outputs a simulated image, based on the center of the simulated image, With a bin width of one, the average value of all values ​​within each axisymmetric ring is calculated and then combined in sequence to obtain a standard reference synthetic spectrum for forward simulation. The simulated image is iteratively adjusted using five variable parameters: sky stray light, atmospheric temperature, filter temperature, optical system focal length, and synthetic spectrum image modulation. The actually observed synthetic spectrum is obtained by performing dark noise removal, discrete bright spot removal, distorted image removal, circle center calculation, concentric circle slope calculation, and image distortion correction on the original image obtained by the rotational temperature spectrum measurement subsystem.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) The present invention adopts three collaborative observation modes with small, medium and large fields of view. The fine spectrum detection subsystem of the small field of view realizes high-precision single-point detection, and the rotational temperature spectrum measurement subsystem of the medium field of view realizes single-point detection with large light flux. The two use collaborative calibration of detection in the same spectral band to obtain high-precision airglow radiation intensity and atmospheric temperature, thereby constructing a more accurate linear relationship between airglow radiation intensity and atmospheric temperature; at the same time, the gravity wave imaging system with a large field of view can detect and obtain airglow radiation field with horizontal two-dimensional resolution capability. Then, through the point-surface fusion detection method and data inversion algorithm, the high-accuracy linear relationship between airglow radiation intensity and atmospheric temperature constructed by single-point detection is expanded and integrated into the airglow radiation field with horizontal two-dimensional resolution capability, thereby obtaining a new parameter of temperature field with the same detection accuracy and horizontal two-dimensional resolution capability. This high-precision two-dimensional temperature field is of great value for the study of near-space photochemical processes, small and medium-scale dynamic processes, climate change, etc.

[0030] 2) The proposed airglow layer gravity wave spectral temperature imaging system utilizes three collaborative observation modes with increasing fields of view: small, medium, and large. The small and medium fields of view of the fine spectrum detection subsystem and the rotational temperature spectrum measurement subsystem ensure the accuracy of point detection, while the large field of view of the large field of view gravity wave imaging subsystem ensures measurement over a larger range, allowing for imaging detection of airglow radiation intensity with two-dimensional horizontal spatial resolution, thereby enabling detection of a large and accurate two-dimensional temperature field.

[0031] 3) The present invention combines the fine spectrum detection subsystem with the rotational temperature spectrum measurement subsystem for joint detection, selects the same detection spectrum band, and couples two different technical systems, grating spectroscopy and interference filter off-axis angular spectroscopy, while coordinating with targeted inversion algorithms such as collaborative calibration. This allows the high spectral resolution of the fine spectrum detection subsystem and the large light flux of the rotational temperature spectrum measurement subsystem to complement each other, thereby obtaining more accurate atmospheric temperature through joint inversion and constructing an accurate linear correlation model between airglow radiation intensity and atmospheric temperature.

[0032] 4) The proposed two-dimensional temperature field point-surface fusion detection method acquires large-scale two-dimensional temperature field data with high spatiotemporal resolution. When gravity wave activity occurs, the airglow radiation intensity disturbance caused by gravity wave activity can be converted into a temperature field disturbance by means of the inversion transformation relationship between the two-dimensional image of airglow radiation intensity and the two-dimensional temperature field. Compared with traditional mathematical models, the real observational data can provide a new path for analyzing the impact mechanism of gravity waves in near-space.

[0033] 5) The airglow layer gravity wave spectral temperature imaging system proposed in this invention adopts a spliced ​​double-step grating as the core component of its fine spectral detection subsystem, and has designed three splicing methods. In combination with a front cylindrical optical lens and a secondary imaging optical path, the effective detection range of the traditional single-piece step grating of 5nm can be widened to 10nm without losing spectral resolution. It can cover at least 7 characteristic airglow spectral lines, greatly improving the temperature detection accuracy, solving the problem of temperature detection during the day, and realizing continuous observation day and night.

[0034] 6) The proposed airglow gravity wave spectral temperature imaging system, in addition to its main optical structure, is also equipped with a housing that enables constant temperature control. A TEC precision temperature controller is installed on the exterior of the motorized filter wheel that rotates the temperature spectrum measurement subsystem, minimizing the risk that the filter's optical properties will change with temperature. Furthermore, the system is equipped with an industrial computer and power module, making it easier to assemble and operate. It is independent of the observation cabin and has strong adaptability to field observations, making it particularly suitable for unmanned automatic observations in extremely cold environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is a schematic diagram of the overall optical and mechanical structure of the airglow layer gravity wave spectrum temperature imaging system of the present invention;

[0036] Figure 2 This is a schematic diagram of a multi-field collaborative observation mode of the airglow layer gravity wave spectral temperature imaging system of the present invention;

[0037] Figure 3 Schematic diagram of the optical structure of the fine spectrum detection subsystem of the present invention;

[0038] Figure 4 Schematic diagram of target airglow radiation characteristic spectrum distribution of the present invention;

[0039] Figure 5 This is a basic principle diagram of the single-step grating and the combined double-step grating light splitting of the present invention;

[0040] Figure 6 This is the overall flow chart of dayglow data processing and temperature inversion of the fine spectrum detection subsystem of the present invention;

[0041] Figure 7 This is the overall flow chart of night airglow data processing and temperature inversion of the fine spectrum detection subsystem of the present invention;

[0042] Figure 8 Schematic diagram of the optical structure of the rotational temperature spectrum measurement subsystem of the present invention;

[0043] Figure 9 This is a flow chart of the multi-parameter adaptive iterative inversion algorithm of the rotational temperature spectrum measurement subsystem of the present invention;

[0044] Figure 10 Schematic diagram of the optical structure of the large-field-of-view gravity wave imaging subsystem of the present invention;

[0045] Figure 11 This is a diagram of the software interface and observation examples of the airglow layer gravity wave spectrum temperature imaging system of the present invention;

[0046] Figure 12 The point-surface fusion data processing method and two-dimensional temperature field inversion process of the present invention;

[0047] Figure 13 This is an example of the two-dimensional temperature field inversion of the present invention;

[0048] Figure: 1 - Fine spectrum detection subsystem; 2 - Rotational temperature spectrum measurement subsystem; 3 - Large field of view gravity wave imaging subsystem; 4 - Optical honeycomb baseplate; 5 - CNC machined chassis; 6 - Quartz glass sealed optical window; 7 - TEC semiconductor air conditioner a; 8 - TEC semiconductor air conditioner b; 9 - Industrial computer control module; 10 - Power supply module; 11 - Waterproof aviation plug; 12 - Front cylindrical optical lens; 13 - Optical slit; 14 - Double-cemented positive lens a; 15 - Double-cemented positive lens b; 16 - Spliced ​​double-step grating; 17 - Plane mirror a; 18 - Narrowband filter a; 19 - Motorized filter wheel a; 20 - Plane mirror b; 21 - Double-cemented positive lens c; 22 - Imaging lens a; 23 - CCD sensor chip a; 24-scientific-grade CCD camera a; 25-light-shielding ring assembly; 26-field diaphragm a; 27-light-shielding lens barrel a; 28-telephoto relay lens; 29-narrow-band filter b; 30-motorized filter wheel b; 31-TEC precision temperature controller; 32-imaging lens b; 33-CCD sensor chip b; 34-scientific-grade CCD camera b; 35-front optical lens b; 36-field diaphragm b; 37-light-shielding lens barrel b; 38-large-aperture double-cemented lens a; 39-large-aperture double-cemented lens b; 40-large-aperture double-cemented lens c; 41-large-aperture double-cemented lens d; 42-narrow-band filter c; 43-motorized filter wheel c; 44-imaging lens c; 45-CCD sensor chip c; 46-scientific-grade CCD camera c. DETAILED DESCRIPTION

[0049] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1:

[0051] This example provides an airglow layer gravity wave spectrum temperature imaging system, including a fine spectrum detection subsystem 1, a rotation temperature spectrum measurement subsystem 2, and a large field of view gravity wave imaging subsystem 3.

[0052] Among them, the fine spectrum detection subsystem 1 includes a front cylindrical optical lens 12, an optical slit 13, a double-cemented positive lens a14, a double-cemented positive lens b15, a spliced ​​double-step grating 16, a narrow-band filter a18, a double-cemented positive lens c21, an imaging lens a22 and a scientific-grade CCD camera a24, which are arranged in sequence along the light incident path; after the light is incident on the spliced ​​double-step grating 16, it is reflected, and the reflected light beam passes through the double-cemented positive lens b15, the narrow-band filter a18, the double-cemented positive lens c21 and the imaging lens a22 in sequence to enter the scientific-grade CCD camera a24.

[0053] The rotational temperature spectrum measurement subsystem 2 includes a light shielding ring group 25, a field stop a26, a telephoto relay lens 28, a narrowband filter b29, an imaging lens b32 and a scientific-grade CCD camera b34, which are sequentially arranged along the light incident path.

[0054] Among them, the large-field-of-view gravitational wave imaging subsystem 3 includes a front optical lens b35, a field aperture b36, a large-aperture doublet lens a38, a large-aperture doublet lens b39, a large-aperture doublet lens c40, a large-aperture doublet lens d41, a narrow-band filter c42, an imaging lens c44 and a scientific-grade CCD camera c46, which are arranged in sequence along the light incident path.

[0055] The fine spectrum detection subsystem 1, the rotational temperature spectrum measurement subsystem 2 and the large-field gravity wave imaging subsystem 3 adopt successively increasing field angles and perform coordinated observations.

[0056] Light from the airglow layer's corresponding field of view is incident on the fine spectrum detection subsystem 1, forming a fine spectrum image of the airglow within the airglow layer's corresponding field of view; light from the airglow layer's corresponding field of view is incident on the rotational temperature spectrum measurement subsystem 2, forming a characteristic spectrum image of the airglow within the airglow layer's corresponding field of view; light from the airglow layer's corresponding field of view is incident on the large-field gravity wave imaging subsystem 3, forming a two-dimensional image with spatial resolution of the airglow radiation intensity within the airglow layer's corresponding field of view; the airglow layer gravity wave spectrum temperature imaging system uses the collaborative inversion of the fine airglow spectrum image and the characteristic airglow spectrum image to obtain high-precision atmospheric temperature and the linear relationship between airglow radiation intensity and atmospheric temperature, and combines the two-dimensional image inversion to transform it into a two-dimensional temperature field with the same resolution.

[0057] The present invention adopts three collaborative observation modes with small, medium and large fields of view. The fine spectrum detection subsystem of the small field of view realizes high-precision single-point detection, and the rotational temperature spectrum measurement subsystem of the medium field of view realizes single-point detection with large light flux. The two use collaborative calibration of detection in the same spectral band to obtain high-precision airglow radiation intensity and atmospheric temperature, thereby constructing a more accurate linear relationship between airglow radiation intensity and atmospheric temperature; at the same time, the gravity wave imaging system with a large field of view can detect and obtain airglow radiation field with horizontal two-dimensional resolution capability, and then through the point-surface fusion detection method and data inversion algorithm, the high-accuracy linear relationship between airglow radiation intensity and atmospheric temperature constructed by single-point detection is expanded and integrated into the airglow radiation field with horizontal two-dimensional resolution capability, thereby obtaining a new parameter of temperature field with the same horizontal two-dimensional resolution capability with the same detection accuracy.

[0058] Example 2:

[0059] like Figure 1As shown, the airglow layer gravity wave spectrum temperature imaging system of this embodiment includes a fine spectrum detection subsystem 1, a rotation temperature spectrum measurement subsystem 2, and a large field of view gravity wave imaging subsystem 3; Figure 3 As shown, the fine spectrum detection subsystem 1 includes a front cylindrical optical lens 12, an optical slit 13, a double cemented positive lens a14, a double cemented positive lens b15, a spliced ​​double-step grating 16, a narrow-band filter a18, a double cemented positive lens c21, an imaging lens a22 and a scientific-grade CCD camera a 24, which are arranged in sequence along the incident path of the light. Figure 8 As shown, the rotational temperature spectrum measurement subsystem 2 includes a light shielding ring group 25, a field stop a26, a telephoto relay lens 28, a narrowband filter b29, an imaging lens b32 and a scientific-grade CCD camera b34 arranged in sequence along the incident path of the light; Figure 10 As shown, the large-field-of-view gravitational wave imaging subsystem 3 includes a front optical lens b35, a field aperture b36, a large-aperture doublet lens a38, a large-aperture doublet lens b39, a large-aperture doublet lens c40, a large-aperture doublet lens d41, a narrow-band filter c42, an imaging lens c44, and a scientific-grade CCD camera c46, which are arranged in sequence along the light incident path.

[0060] like Figure 2 As shown, light within a field of view of 1.8~2.5° in the airglow layer is incident on the fine spectrum detection subsystem 1, and a fine airglow spectrum image for inverting the average temperature within the annular region of the field of view is formed on the scientific-grade CCD camera a 24; light within a field of view of 8.5~11.5° in the airglow layer is incident on the rotational temperature spectrum measurement subsystem 2, and an airglow characteristic spectrum image for inverting the average temperature within the annular region of the field of view is formed on the scientific-grade CCD camera b34; light within a field of view of 90°~110° in the airglow layer is incident on the large-field gravity wave imaging subsystem 3, and a two-dimensional image with spatial resolution of the airglow radiation intensity within the field of view is formed on the scientific-grade CCD camera c46.

[0061] The three subsystems of this embodiment have three different fields of view and perform synchronous detection. The detection area and the detection target are organically coordinated. Later, through image and data processing, the fine spectrum detection subsystem 1 and the rotational temperature spectrum measurement subsystem 2 are collaboratively calibrated. Based on the obtained spectral image, high-precision inversion of atmospheric temperature can be achieved, and a linear relationship between airglow radiation intensity and atmospheric temperature can be obtained. The large-field-of-view gravity wave imaging subsystem 3 only obtains gridded observations of airglow radiation intensity. However, the linear relationship between airglow radiation intensity and atmospheric temperature obtained through the collaboration of the fine spectrum detection subsystem 1 and the rotational temperature spectrum measurement subsystem 2 can realize the inversion of the two-dimensional image of airglow radiation intensity into a two-dimensional temperature field with the same resolution.

[0062] Example 3:

[0063] like Figure 1 As shown, the overall optomechanical architecture of the airglow layer gravity wave spectral temperature imaging system of this embodiment utilizes a modular integrated design. Its core components consist of three subsystems: a fine spectral detection subsystem 1, a rotational temperature spectral measurement subsystem 2, and a large-field-of-view gravity wave imaging subsystem 3. All three subsystems are housed within a CNC-machined chassis 5 and supported by an optical honeycomb baseplate 4 at the bottom of the CNC-machined chassis 5. The optical honeycomb baseplate 4 is securely fastened to the chassis 5 with screws or other rigid connectors. Standardized interfaces are provided on the optical honeycomb baseplate 4 to support hot-swappable upgrades of the three subsystems. Three quartz glass sealed optical windows 6 are positioned at the top of the CNC-machined chassis 5, corresponding to the fields of view of the three subsystems. These windows have a transmittance greater than 92% and are coated with a 300-1100nm anti-reflection coating. They are precisely aligned with the fields of view of each subsystem. TEC semiconductor air conditioners a7 and b8 are positioned diagonally on the left and right side walls of the CNC machining chassis 5. These two air conditioners utilize a dual-unit temperature control strategy to achieve precise thermal environment control of 20±0.5°C. Combined with a multi-layer anti-reflection coated quartz glass sealed optical window 6, they can effectively handle extreme ambient temperature fluctuations of -40°C to +40°C. The side walls of the CNC machining chassis 5 also feature an industrial computer control module 9, a power supply module 10, and a waterproof aviation plug 11. The industrial computer control module 9 is positioned below the TEC semiconductor air conditioner a7 to facilitate rapid heat filtration through the air duct. The waterproof aviation plug 11, located below the industrial computer control module 9, connects to internal and external power and network connections. The power supply module 10 is located on the other side wall of the CNC machining chassis 5, above the TEC semiconductor air conditioner b8.

[0064] like Figure 2 As shown in the figure, in the multi-field collaborative observation mode of the airglow layer gravity wave spectral temperature imaging system, with the natural radiation of airglow at an altitude of 85~240km as the light source, the fine spectrum detection subsystem 1 detects the fine spectrum radiation intensity of the airglow within a field of view of about 1.8~2.5°, with a spectral resolution of up to 0.01nm, and can invert the average temperature within the annular area of ​​the field of view; the rotational temperature spectrum measurement subsystem 2 detects the characteristic spectrum radiation intensity of the airglow within a field of view of about ~8.5~11.5°, with a spectral resolution of up to 0.2~0.8nm, and can invert the average temperature within the annular area of ​​the field of view; the large-field gravity wave imaging subsystem 3 detects the airglow radiation intensity within a field of view of about 90°~110°. This subsystem is an imaging detection system, which can use the high resolution of the detector to realize grid detection of the airglow radiation intensity within a rectangular area, that is, a two-dimensional image detection with spatial resolution of 0.1×0.1km. 2 ~1.0×1.0km 2The field of view of the autonomously adjustable large-field gravity wave imaging subsystem 3 can ensure measurement of a larger range without causing a lot of imaging distortion that is difficult to handle.

[0065] like Figure 3 As shown, in the optical structure of the fine spectrum detection subsystem 1 of this embodiment, a front cylindrical optical lens 12 is provided at the top, and an optical slit 13 is provided at the focal plane below the front cylindrical optical lens 12. The optical slit 13 is driven by piezoelectric ceramics, with a dynamic opening and closing adjustment range of 5~50μm and a step accuracy of 0.1μm. A V-groove blackened structure with a reflectivity of <0.1%@400-1000nm is provided on the inner wall of the slit. A double-cemented positive lens a14 is provided close to the optical slit 13, and a double-cemented positive lens b15 is provided at a certain distance. The optical slit 13 is located at one focal length of the double-cemented positive lens b15. A spliced ​​double-step grating 16 is provided behind the double-cemented positive lens b15. The double-step grating is composed of two step gratings with different characteristics. The set deflection angle is related to the Littrow angle of the step grating itself. The splicing slit width is ≤5μm and the diffraction efficiency is >80%. The grating mounting seat adopts a thermal expansion coefficient of 1.2×10⁻ 6 / ℃ Invar material matches the grating substrate, and the thermal drift compensation accuracy reaches 0.001nm / ℃; in the optical path reflection path, a plane mirror a17 is set, its height is close to that of the double-cemented positive lens a14 but is located on the side of the vertical optical axis, the purpose is to reflect the light beam from bottom to top into a horizontal light beam, but without interfering with the light beam from top to bottom; on the other side of the plane mirror a17 relative to the optical axis, an electric filter wheel a19 is provided with a narrowband filter a18, wherein the position of the narrowband filter a18 is located at one focal length of the double-cemented positive lens b15; behind it, a plane mirror b20 is further provided to reflect the horizontal light beam back into a vertical light beam; then, a double-cemented positive lens c21, an imaging lens a22, a CCD sensor chip a23, and a scientific-grade CCD camera a24 are arranged in sequence, wherein the CCD sensor chip a23 is located in the scientific-grade CCD camera a, and the above-mentioned optical components are all supported on the corresponding optical honeycomb base plate 4 by support rods.

[0066] The overall optical path structure of the fine spectrum detection subsystem 1 is set as a secondary imaging optical path. After the light beam from the middle and upper atmospheric airglow radiation enters the fine spectrum detection subsystem 1 vertically from top to bottom, it will first be converged into a linear light band by the front cylindrical optical lens 12. Compared with ordinary lenses, the front cylindrical optical lens 12 can maximize the luminous flux and light beam utilization to cooperate with the filtering effect of the optical slit 13; after passing through the optical slit 13, the light beam becomes a large-angle divergent light beam. At this time, the object side of the light path is formed at the optical slit 13; then, the double-cemented positive lens a14 is used to appropriately shrink the large-angle divergent light beam so that the light spot of the divergent light beam does not exceed the clear aperture of the double-cemented positive lens b15; the divergent light beam then passes through the action of the double-cemented positive lens b15 and is transformed into a parallel The light beam enters the reflective surface of the split-echelon grating 16, undergoes spectral splitting and reflection, and then re-enters the double-cemented positive lens b15 from bottom to top along the grating's Littrow angle. At this point, the parallel beam becomes a converging beam and travels from bottom to top to the plane mirror a17. It then converges on the narrowband filter a18, forming the first imaging position on the object side of the optical slit 13. This position has the smallest spot size, maximizing the effective aperture of the narrowband filter a18. The light beam then diverges again, passing through the plane mirror b20 and the double-cemented positive lens c21, becoming a parallel beam. Finally, it passes through the imaging lens a22 and converges onto the CCD sensor chip a23, forming the second imaging position on the object side of the optical slit 13. After traversing the overall optical path and the interaction of the split-echelon grating 16, a linear spectral image is ultimately formed on the CCD sensor chip a23.

[0067] like Figure 4 As shown in the figure, the target airglow radiation characteristic spectrum distribution diagram is shown. The Meinel band of OH molecules is one of the most important radiations in night airglow and day airglow. It has a rich vibration-rotation spectrum from visible light to infrared band. Among them, the seven spectrum lines P1(2), P1(3), P1(4), P1(5), P2(3), P2(4), and P2(5) are widely spaced and have strong spectrum line intensities. Except for P2(3) and O +Aside from the overlap, the other six lines are suitable for temperature inversion. The influence of water vapor in this band is relatively small, and common optical components are available with infrared-enhancing coatings. Specially treated CCD chips can also achieve high quantum efficiency in this band, exceeding 70%. However, the bandwidth of light separation by a typical single-piece echelle grating is very limited, with an effective free spectral range of only approximately 5nm, covering only one or two weak spectral lines and one or two strong spectral lines. This is insufficient for accurately inverting the atmospheric temperature of the airglow layer. Therefore, this embodiment utilizes a spliced ​​double-echelon grating 16 composed of two echelon gratings, wherein one echelon grating is used to cover P1(2), P1(3), P2(3), and P2(4), and the other is used to cover P1(4), P1(5), and P2(5), thereby extending the effective bandwidth to 10 nm and covering 7 spectral lines of the OH (8-3) airglow band, including 4 strong spectral lines and 3 weak spectral lines, thereby being used for accurate inversion of the atmospheric temperature of the airglow layer.

[0068] like Figure 5 As shown in FIG, a schematic diagram of the basic principle of light splitting of a single-step grating and a combined double-step grating of this embodiment is shown. Figure 5 As shown in (a), the common 31 l / mm, 63° incident angle of the step grating as an example, take the two farthest spectral lines P1(2) (731.6 nm) and P1(5) (740.2 nm) as the detection target, the diffraction efficiency is the highest when it is closest to the Littrow angle, but the two spectral lines correspond to different orders 79 and 78 respectively, and the corresponding free spectral range is only about 10nm. If the non-Littrow angle condition is used for incidence, and the two spectral lines are allowed to enter the same order, the diffraction angle will deviate from the Littrow angle by a large margin, the diffraction efficiency will drop seriously, and both will be at the detection boundary, and will appear at the edge of the field of view during imaging. The imaging quality is very poor, and no effective information can be obtained. In fact, the effective free spectral range that can be used is only about 5nm. Figure 5 Middle (b), Figure 5 (c) and Figure 5 (d) shows three design solutions for the splicing conditions and parameters of the spliced ​​double-step grating 16 proposed in this embodiment. a 1 、 a 2 are the grating constants of the two step gratings, m 1. m 2 is the diffraction order, θ m1 、 θ m2 is the diffraction angle, λ 1 、 λ 2is the wavelength, θ i1 、 θ i2 is the angle of incidence, θ t is the Littrow angle, then the three options are as follows:

[0069] (1) The first option: Figure 5 As shown in (b), the same dual gratings are used but with different splicing angles, namely:

[0070] , (1);

[0071] Commercial gratings can be used, but deviation from the Littrow angle will cause a certain degree of decrease in diffraction efficiency, and the dual-wavelength diffraction angles are inconsistent. The diffraction efficiency needs to be calibrated and consistency compensation corrected later.

[0072] (2) If Figure 5 As shown in (c), the double gratings are spliced ​​in different ways with different Littrow angles and splicing angles, namely:

[0073] , (2);

[0074] A custom grating is required, with the Littrow wavelength designed as the target wavelength, and both the incident and exit angles are at the Littrow angle. This increases the development cost, but theoretically the diffraction efficiency can be maintained at the highest, and subsequent calibration is simple.

[0075] (3) If Figure 5 As shown in (d), a double grating with different grating constants and the same splicing angle is used.

[0076] , (3);

[0077] The grating needs to be customized to keep the Littrow angle unchanged, but the line density needs to meet the proportional relationship of the target wavelength. The development cost is moderate. Since the double grating can be spliced ​​in parallel, the optical path construction is more convenient and the stability is high.

[0078] like Figure 8As shown, in the optical structure of the rotational temperature spectrum measurement subsystem 2, all optical elements are fastened to the light-shielding lens barrel a27, and a light-shielding ring group 25 composed of multiple layers of anodized aluminum light-shielding rings with gradually decreasing inner diameters is set on the top of the light-shielding ring group 25. The surface of each layer is blackened by micro-arc oxidation to make the reflectivity less than 0.5%, forming a composite stray light suppression system with the light-shielding lens barrel a27; a field stop a26 is set close to the lower end of the light-shielding ring group 25, and a telephoto relay lens 28 is set at a certain distance, which has good phase difference correction capability, wherein the field stop a26 is located at the front focus of the telephoto relay lens 28; the telephoto relay lens 28 is fixed to the light inlet of the electric filter wheel b30 set behind it, and the light-shielding lens barrel a27 is set in the middle of the light-shielding lens barrel a27, and a narrow band is set inside the electric filter wheel b30. Filter b29 uses an extremely narrowband interference technology system with a bandwidth of 0.25~0.5nm. The drift of its central wavelength caused by temperature changes will cause a large error in spectral line detection. Therefore, a TEC precision temperature controller 31 is set on the outer shell of the electric filter wheel b30 to implement precise temperature control of 20℃±0.1℃ for the extremely narrowband interference filter. Its temperature control output end is located in the cavity of the electric filter wheel b30 for placing the narrowband filter b29, which is relatively close to the narrowband filter b29; an imaging lens b32 and a scientific-grade CCD camera b34 are set close to the outlet end of the electric filter wheel b30, among which the CCD sensor chip b33 is located inside the scientific-grade CCD camera b34, and the scientific-grade CCD camera b34 is connected to the bottom end of the light-shielding lens barrel a27.

[0079] The rotational temperature spectrum measurement subsystem adopts a photometric optical path as a whole. The airglow radiation from the sky airglow layer within a field of view angle of approximately 8.5~11.5° converges to the field of view aperture a26. Under the action of the telephoto relay lens 28, it is converted into a parallel beam and incident on the narrowband filter b29 at a maximum angle of approximately 4.3~5.8°, performing axisymmetric spectral splitting. Since the narrowband filter b29 has different transmittance functions for different angles, after passing through the imaging lens b32 provided thereafter, different spectral radiation will converge to different pixel positions of the CCD sensor chip b33. The positions with spectral line radiation will appear as bright rings, while the positions without spectral lines, that is, the spectral line intervals, will appear as dark rings, thereby realizing imaging spectrum detection. This detection mode uses the principle of off-axis angular spectroscopy of interference filters based on the photometric optical path, making full use of all the airglow radiation from the sky's airglow layer within a field of view of about 8.5~11.5°. Compared with traditional slit-type spectrometers, the light flux can be increased by at least 10 2 ~10 3 Therefore, it has great advantages in image signal-to-noise ratio and uncertainty of detection values.

[0080] like Figure 10As shown in the figure, in the optical structure of the large-field-of-view gravity wave imaging subsystem 3, all optical elements are fastened to the light-shielding lens barrel b37. A front optical lens b35 is set on the top of the light-shielding lens barrel b37, which can generally adopt a fisheye lens or a wide-angle lens with a large field of view and zero distortion. A field stop b36 is set closely below it, which can realize the adjustment function of the light aperture with a diameter of 10mm~45mm; then a large-aperture double-cemented lens a38 and a large-aperture double-cemented lens b39 are set at a certain distance. The two lenses have the same focal length, generally 100mm~150mm, and both adopt a double-cemented positive lens design. The optical surfaces are placed relative to each other to form a Gaussian lens group to realize the function of field mirror and reduce the influence of aberrations such as dispersion, spherical aberration, and field curvature. The focal plane of the front optical lens b35 is set Located at the center of the large-aperture doublet lens a38; a large-aperture doublet lens c40 and a large-aperture doublet lens d41 are set at a certain distance. The two lenses have the same focal length, generally 300mm~400mm, and both adopt a doublet positive lens design. The optical surfaces are placed opposite each other to form a Gaussian lens group; followed by a motorized filter wheel c43, which is set in the middle of the light-shielding lens barrel b37. A narrow-band filter c42 is fixed inside the motorized filter wheel c43; an imaging lens c44 and a scientific-grade CCD camera c46 are set close to the outlet end of the motorized filter wheel c43, among which the CCD sensor chip c45 is located inside the scientific-grade CCD camera c46, and the scientific-grade CCD camera c46 is connected to the bottom of the light-shielding lens barrel b37.

[0081] The overall optical path structure of the large-field-of-view gravity wave imaging subsystem 3 is configured as a secondary imaging optical path. After the light beam from the airglow radiation of the middle and upper atmosphere enters the large-field-of-view gravity wave imaging subsystem 3, it is first converged by the front optical lens b35 to the center position of the large-aperture doublet lens a38, which is the primary imaging position. After the field lens function of the large-aperture doublet lens a38 and the large-aperture doublet lens b39, the outward expansion angle of the light beam emitted by the front optical lens b35 can be greatly reduced, and the light transmittance at the edge of the final image can be greatly increased. The subsequent outgoing light beam converges in the reverse direction of the optical fiber to form a virtual image. The virtual image position needs to be located at one times the combined focal length of the lens group composed of the large-aperture doublet lens c40 and the large-aperture doublet lens d41, so that the divergent light beam after passing through this lens group is converted into a parallel beam. Then, through the action of the narrowband filter c42 and the imaging lens c44, a secondary image is formed on the CCD sensor chip c45. At this point, the grayscale value of each square pixel on the CCD sensor chip c45 corresponds to the airglow radiation intensity value of each square area in the sky, thus recording the two-dimensional distribution of the radiation intensity level of the airglow layer in the sky. If there is a gravity wave disturbance, it will form a periodic disturbance of the radiation intensity of a certain area of ​​the airglow layer. In the image obtained by the CCD sensor chip c45, the grayscale value of the corresponding area will show a periodic disturbance. These disturbances are the result of the gravity wave. Figure 11 As shown, in the software interface and observation example of the airglow layer gravity wave spectral temperature imaging system of this embodiment, the fine spectrum detection subsystem 1 can detect multiple clear airglow radiation spectra and has the advantage of high resolution. The rotational temperature spectrum measurement subsystem 2 can obtain axially symmetrical annular images of different airglow bands and has the advantage of large light flux. The large-field gravity wave imaging subsystem 3 can obtain the distribution of airglow intensity and obvious gravity wave activities.

[0082] Example 4:

[0083] This embodiment provides a point-surface fusion data processing method and a two-dimensional temperature field inversion method for the airglow layer gravity wave spectral temperature imaging system based on the second embodiment.

[0084] like Figure 12 The specific steps are as follows:

[0085] Step (1): using the original image obtained by the fine spectrum detection subsystem 1, the airglow radiation intensity and atmospheric temperature in the small field of view (1.8°~2.5°) are inverted; at the same time, using the original image obtained by the rotational temperature spectrum measurement subsystem 2, the airglow radiation intensity and atmospheric temperature in the medium field of view (8.5°~11.5°) are inverted.

[0086] Step (2) is to use the multi-parameter fine calibration in the laboratory to calculate the airglow radiation intensity inverted by the fine spectrum detection subsystem 1 and the rotational temperature spectrum measurement subsystem 2 through spectrum fusion calculation and input it into the data fusion model to eliminate the systematic error and obtain high-precision atmospheric temperature. T At the same time, the high-precision atmospheric temperature obtained by the two subsystems is input into the data fusion model, and the airglow radiation intensity is established by regression analysis. I and atmospheric temperature T The mathematical relationship between IT The relationship is generally a linear relationship.

[0087] Step (3) uses the original image obtained by the large-field gravity wave imaging subsystem 3 to invert the horizontal two-dimensional airglow radiation intensity within the large field of view: 90°~110°; then, based on the laboratory fine calibration results, the spectrum fusion calculation is performed with the airglow radiation intensity obtained by the fine spectrum detection subsystem 1 and the rotation temperature spectrum measurement subsystem 2 to convert the original horizontal two-dimensional airglow radiation intensity into the horizontal two-dimensional airglow radiation intensity within the common spectrum of the three subsystems. I 2D 。

[0088] Step (4), using the relationship between airglow radiation intensity and atmospheric temperature constructed in step (2) ITMathematical relationship, the two-dimensional airglow radiation intensity I 2D Converted into horizontal two-dimensional temperature field through mathematical calculation T 2D If gravity wave activity occurs, since large-scale two-dimensional temperature field data has the characteristics of high temporal and spatial resolution, the airglow radiation intensity disturbance caused by gravity wave activity can be converted into a disturbance to the temperature field with the help of the inversion transformation relationship between the two-dimensional image of airglow radiation intensity and the two-dimensional temperature field, thereby extracting the two-dimensional airglow radiation intensity distribution and temperature disturbance intensity distribution results caused by gravity waves.

[0089] Among them, in step (1), the original image obtained by the fine spectrum detection subsystem 1 is used to invert the airglow radiation intensity and atmospheric temperature within the small field of view. Since airglow radiation exists both during the day and at night, namely daytime airglow and nighttime airglow, their radiation characteristics are quite different. In addition, due to the interference of solar background light during the day, the detection and extraction of effective information are quite different. Therefore, the inversion methods need to be designed respectively. Specifically, Figure 6 and Figure 7 shown.

[0090] like Figure 6 As shown in the figure, in the overall process of daytime airglow data processing and temperature inversion of the fine spectrum detection subsystem 1, the original airglow image data needs to go through the steps of eliminating cosmic rays, denoising, normal coefficient correction, ring stripe tilt correction and pincushion distortion correction in sequence. Denoising includes removing background dark noise, bias, readout noise, etc., so as to obtain effective image data that can be directly used in the subsequent inversion process. Subsequently, the signal characteristics in the large interval area of ​​the two spectral lines P1 (4) and P2 (5) are used as reference background stray light signals to remove them from the effective image data, generating image data that can be used for inversion. Based on the laboratory calibration data, the positions of each spectral line are accurately located and corrected to obtain the original spectrum data. For fine spectrum extraction, first, multiple groups of original spectrum data at the highest solar altitude angle on the day are averaged to obtain the sun and sky background reference spectrum, which is normalized and removed from the original spectrum data. The remaining spectrum data are then corrected for the Ring effect, combined with the dual-band spectrum, and corrected for the secondary positioning of the spectrum to obtain the final daytime airglow fine spectrum. The rotational temperature inversion process begins with the daylight glow fine spectrum. We will use the multi-line ratio method or the slope method to invert the rotational temperature, and use the relevant results of the previous calibration and simulation to jointly perform error assessment of the temperature inversion.

[0091] like Figure 7As shown in the figure, in the overall process of nightglow data processing and temperature inversion of the fine spectrum detection subsystem 1, the original image data needs to go through the steps of eliminating cosmic rays, removing background dark noise, and correcting pincushion distortion in sequence to obtain valid image data that can be directly used in the subsequent inversion process. Among them, the median filtering method is used to preliminarily filter out the background noise of the original image, and the CCD background dark noise under the shielding condition is subtracted. The effective value area is filtered out by the received light intensity, and the misalignment correction value of each row of pixels is calculated by judging the peak position of the received light intensity in each row of pixels to further correct the pincushion distortion introduced by the lens to obtain a fine nightglow spectrum image. The natural signal peak of the spectral line is obtained by superimposing the column pixels, and the residual background noise is nonlinearly fitted by the area around the signal peak to remove it from the original spectral data. The spectral line signal area is evaluated, and the remaining spectral signal peaks are subjected to Gaussian fitting. The intensity of each spectral line is extracted to obtain the final nightglow fine spectrum intensity data. The slope method is used to invert the rotational temperature based on the spectral parameters of the HITRAN database. The temperature results of different algorithms in the process of processing residual background noise are compared to further complete the error evaluation of temperature inversion.

[0092] In step (1), the original image obtained by the rotational temperature spectrum measurement subsystem 2 is used to invert the airglow radiation intensity and atmospheric temperature in the central field of view: 8.5°~11.5°. The specific method is as follows: Figure 9 As shown in the figure, in the multi-parameter adaptive iterative inversion algorithm of the rotational temperature spectrum measurement subsystem, the inversion process is to compare the synthetic spectra at different temperatures simulated by the forward model with the synthetic spectra of the actual observation, and calculate the minimum average difference between the two to determine the actual observed temperature. It includes three modules:

[0093] (1) Five variable parameters, namely sky stray light, atmospheric temperature, filter temperature, optical system focal length and synthetic spectral image modulation, are added to module a, and the variation range is set to adjust the simulated image in module b.

[0094] (2) Module b is the forward model, which consists of four submodules. The airglow radiation spectrum, atmospheric radiation transmission, and optical system submodules simulate the airglow radiation intensity received by the rotational temperature spectrum measurement subsystem 2. The CCD sensor module then performs photoelectric conversion to output a simulated image. Based on the center of the simulated image, with a width of one bin, the average value of all values ​​within each axisymmetric ring is calculated and then combined in sequence to obtain a standard reference synthetic spectrum for the forward simulation.

[0095] (3) Module c is an image processing module, which performs dark noise removal, discrete bright spot removal, distorted image removal, circle center calculation, concentric circle slope calculation, image distortion correction and other processes on the original image to calculate and output the synthetic spectrum of the actual observation data.

[0096] Iterative calculation process: First, process the sky stray light and preliminarily determine the atmospheric temperature; second, adjust the filter temperature and the focal length of the optical system; and third, obtain the synthetic spectrum correction curve. Once these three steps are completed, an iterative calculation is complete. In one iterative calculation, the five parameters are iterated sequentially according to the three steps above. At this point, the other parameters that initially determined the atmospheric temperature have changed, and therefore the corresponding atmospheric temperature should also be adjusted. The sky stray light, filter temperature, and focal length obtained from this iterative calculation are used as the initial parameter values ​​for the next iterative calculation to re-derive the atmospheric temperature. At the end of each iterative calculation, an average difference is obtained. If the difference between the current average difference and the previous average difference is less than 0.01%, the loop ends when the judgment criteria are met. The inverted temperature is now the actual observed atmospheric temperature, and the inversion process is complete.

[0097] like Figure 13 As shown in the two-dimensional temperature field inversion example of the embodiment, the left figure is the horizontal two-dimensional airglow radiation intensity obtained by the large-field gravity wave imaging subsystem 3; the middle figure is the inversion result based on the fine spectrum detection subsystem 1 and the rotational temperature spectrum measurement subsystem 2, and the IT relationship between the airglow radiation intensity and the atmospheric temperature is established by regression analysis: T=170.31+0.52I; the right figure is the inversion result based on the fine spectrum detection subsystem 1 and the rotational temperature spectrum measurement subsystem 2. Figure 13 The two-dimensional temperature field distribution results inverted using the method in [1]. The figure on the right shows the temperature distribution within a spatial range of approximately 90 km × 90 km within the OH (8-3) spectrum at an altitude of 87 km. Between 170 and 210 K, a wave-like structure caused by gravity wave activity is evident on the left. The calculated wavelength is approximately 4.3 km, the propagation direction is at an angle of 318° with respect to true north, the radiation intensity amplitude is approximately 38 Rayleigh, and the temperature amplitude is approximately 7.6 K.

[0098] The technical solutions of the present invention are not limited to the above-mentioned embodiments, and any technical solutions obtained by equivalent replacement methods fall within the scope of protection required by the present invention.

Claims

1. An airglow layer gravity wave spectral temperature imaging system, characterized by: Including fine spectrum detection subsystem, rotation temperature spectrum measurement subsystem, large field of view gravity wave imaging subsystem; The fine spectrum detection subsystem includes a front cylindrical optical lens, an optical slit, a double-cemented positive lens a, a double-cemented positive lens b, a spliced ​​double-step grating, a narrow-band filter a, a double-cemented positive lens c, an imaging lens a, and a scientific-grade CCD camera a, which are sequentially arranged along the light incident path; after the light is incident on the spliced ​​double-step grating, it is reflected, and the reflected light beam passes through the double-cemented positive lens b, the narrow-band filter a, the double-cemented positive lens c, and the imaging lens a in sequence and enters the scientific-grade CCD camera a; The rotational temperature spectrum measurement subsystem includes a light shielding ring group, a field stop a, a telephoto relay lens, a narrowband filter b, an imaging lens b and a scientific-grade CCD camera b, which are sequentially arranged along the light incident path; The large-field-of-view gravity wave imaging subsystem includes a front optical lens b, a field stop b, a large-aperture doublet lens a, a large-aperture doublet lens b, a large-aperture doublet lens c, a large-aperture doublet lens d, a narrow-band filter c, an imaging lens c, and a scientific-grade CCD camera c, which are sequentially arranged along the light incident path; The fine spectrum detection subsystem, the rotational temperature spectrum measurement subsystem and the large field-of-view gravity wave imaging subsystem adopt successively increasing field angles and perform coordinated observations; The light of the airglow layer corresponding to the field of view is incident on the fine spectrum detection subsystem, forming a fine spectrum image of the airglow in the field of view corresponding to the airglow layer; The light of the airglow layer corresponding to the field of view is incident on the rotational temperature spectrum measurement subsystem, forming an airglow characteristic spectrum image in the field of view corresponding to the airglow layer; The light from the airglow layer corresponding to the field of view is incident on the large-field gravity wave imaging subsystem, forming a two-dimensional image with spatial resolution of the airglow radiation intensity in the airglow layer corresponding to the field of view; The airglow layer gravity wave spectral temperature imaging system uses the collaborative inversion of airglow fine spectral images and airglow characteristic spectral images to obtain high-precision atmospheric temperature and the linear relationship between airglow radiation intensity and atmospheric temperature, and combines it with two-dimensional image inversion to transform it into a two-dimensional temperature field with the same resolution.

2. The airglow layer gravity wave spectral temperature imaging system according to claim 1, characterized in that: The spliced ​​double-step grating is formed by splicing a first step grating and a second step grating. The parameter relationship between the two step gratings in the spliced ​​double-step grating satisfies the following formula: ， ； Alternatively, the parameter relationship between the two step gratings in the spliced ​​double step grating satisfies the following formula: ， ； Alternatively, the parameter relationship between the two step gratings in the spliced ​​double step grating satisfies the following formula: ， ； in, a 1 、 a 2 are the grating constants of the first and second step gratings, m 1. m 2 are the diffraction orders of the first and second step gratings, θ m1 、 θ m2 are the diffraction angles of the first and second step gratings, λ 1 、 λ 2 are the wavelengths of the first and second echelle gratings, θ i1 、 θ i2 are the incident angles of the first and second step gratings, θ t Littrow angle.

3. The airglow layer gravity wave spectral temperature imaging system according to claim 2, characterized in that: The increasing field of view angles correspond to: the field of view angle of the fine spectrum detection subsystem is 1.8~2.5°, the field of view angle of the rotational temperature spectrum measurement subsystem is 8.5~11.5°, and the field of view angle of the large field of view gravity wave imaging subsystem is 90°~110°.

4. The airglow layer gravity wave spectral temperature imaging system according to claim 3, characterized in that: The optical slit in the fine spectrum detection subsystem is arranged at the lower focal plane of the front cylindrical optical lens, and is arranged closely to the double-cemented positive lens a, and is arranged at one focal length of the double-cemented positive lens b; the narrowband filter a is arranged on the electric filter wheel a and is located at one focal length of the double-cemented positive lens b. Plane mirrors a and plane mirrors b are provided on both sides of the narrowband filter a. Plane mirror a reflects the bottom-up light beam reflected by the spliced ​​double-step grating into a horizontal light beam, and plane mirror b reflects the horizontal light beam into a vertical light beam.

5. The airglow layer gravity wave spectral temperature imaging system according to claim 4, characterized in that: The rotational temperature spectrum measurement subsystem is arranged on the light-shielding lens barrel a. The light-shielding ring group is composed of multiple layers of nested anodized aluminum light-shielding rings and is arranged on the top of the light-shielding lens barrel a. The field stop a is arranged close to the lower end of the light-shielding ring group and is located at the front focus of the telephoto relay lens; the narrowband filter b is arranged on the electric filter wheel b located in the middle of the light-shielding lens barrel a, and the housing of the electric filter wheel b is equipped with a TEC precision temperature controller. The scientific-grade CCD camera b is arranged at the bottom end of the light-shielding lens barrel a.

6. The airglow layer gravity wave spectral temperature imaging system according to claim 5, characterized in that: The large-field-of-view gravitational wave imaging subsystem is disposed on a light-shielding lens barrel b. The front optical lens b is disposed at the top of the light-shielding lens barrel b. The field stop b is closely attached to the bottom of the front optical lens b. The large-aperture doublet lens a and the large-aperture doublet lens b have the same focal length, ranging from 100 mm to 150 mm. The focal plane of the front optical lens b is located at the center of the large-aperture doublet lens a. The large-aperture doublet lens c and the large-aperture doublet lens d have the same focal length, ranging from 300 mm to 400 mm. A narrowband filter c is disposed on a motorized filter wheel c located in the middle of the light-shielding lens barrel b. A scientific-grade CCD camera c is disposed at the bottom of the light-shielding lens barrel b.

7. The airglow layer gravity wave spectral temperature imaging system according to claim 6, characterized in that: It also includes a CNC-processed chassis shell, in which the fine spectrum detection subsystem, the rotational temperature spectrum measurement subsystem and the large-field-of-view gravity wave imaging subsystem are arranged. The subsystem is supported on an optical honeycomb base plate provided at the bottom of the CNC-processed chassis shell. The top of the CNC-processed chassis shell is provided with three quartz glass sealed optical windows that are precisely aligned with the fields of view of the three subsystems respectively. The transmittance of the quartz glass sealed optical windows is greater than 92%, and they are coated with a 300-1100nm anti-reflection film. TEC semiconductor air conditioners a and TEC semiconductor air conditioners b are diagonally arranged on two opposite side walls of the CNC-processed chassis shell. An industrial computer control module is provided below the TEC semiconductor air conditioner a on the side wall of the CNC-processed chassis shell, a waterproof aviation plug is provided below the industrial computer control module, and a power module is provided above the TEC semiconductor air conditioner b.

8. A two-dimensional temperature field point-surface fusion inversion method based on the airglow layer gravity wave spectrum temperature imaging system according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: Use the fine spectrum detection subsystem to obtain the fine spectrum image of airglow and invert the airglow radiation intensity and atmospheric temperature in the corresponding field of view; The rotational temperature spectrum measurement subsystem is used to obtain the characteristic spectrum image of airglow and invert the airglow radiation intensity and atmospheric temperature in the corresponding field of view; Step 2: Based on the laboratory's multi-parameter fine calibration, the airglow radiation intensity inverted by the fine spectrum detection subsystem and the rotational temperature spectrum measurement subsystem is calculated through spectral segment fusion, and the airglow radiation intensity calculated after spectral segment fusion is fused with the atmospheric temperature inverted by the two subsystems to eliminate the systematic error and obtain high-precision atmospheric temperature. T , and regression analysis was used to establish the airglow radiation intensity I and atmospheric temperature T The mathematical relationship between IT relation; Step 3: Use the large-field-of-view gravity wave imaging subsystem to acquire a two-dimensional image and invert the horizontal two-dimensional airglow radiation intensity within the large field of view; Based on the laboratory fine calibration, the horizontal two-dimensional airglow radiation intensity is converted into the horizontal two-dimensional airglow radiation intensity within the common spectrum of the three subsystems I 2D ; Step 4: Use the data built in step 2 IT Relationship, the horizontal two-dimensional airglow radiation intensity in step 3 I 2D Converted into horizontal two-dimensional temperature field T 2D .

9. The two-dimensional temperature field point-surface fusion inversion method according to claim 8, characterized in that: The method for inverting the daytime airglow radiation intensity and atmospheric temperature using the fine spectrum image of the airglow obtained by the fine spectrum detection subsystem in step 1 is: The original image data of dayglow acquired by the fine spectrum detection subsystem is processed to remove noise and background stray light signals to obtain inversion image data; Based on laboratory calibration data, the position of each spectral line is accurately located and corrected to obtain the original spectral data; Fine spectrum extraction is performed on the original spectral data. First, multiple sets of original spectral data at the highest solar altitude angle on that day are averaged to obtain the sun and sky background reference spectra. After normalization, these reference spectra are removed from the original spectral data. The remaining spectral data are then corrected for the Ring effect, combined with two-band spectra, and corrected for spectral secondary positioning to obtain the final daylight glow fine spectrum. The rotation temperature is inverted using the multi-line ratio method or the slope method to obtain the dayglow rotation temperature; The method for inverting the nighttime airglow radiation intensity and atmospheric temperature using the fine spectrum image of the airglow obtained by the fine spectrum detection subsystem in step 1 is as follows: De-noising the raw image data of night airglow acquired by the fine spectrum detection subsystem; The denoised image data is filtered out using the received light intensity to extract the valid value area. The peak position of the received light intensity in each row of pixels is determined, and the misalignment correction value of each row of pixels is calculated to correct the pincushion distortion introduced by the lens, thereby obtaining a fine spectrum image of the night airglow. The night airglow fine spectrum image is subjected to nonlinear fitting to remove the residual background noise; The remaining spectral signal peaks are then subjected to Gaussian fitting to obtain the final night airglow fine spectral intensity data; The slope method is used to invert the rotation temperature and obtain the nightglow rotation temperature.

10. The two-dimensional temperature field point-surface fusion inversion method according to claim 9, characterized in that: The method for inverting the airglow radiation intensity and atmospheric temperature from the airglow characteristic spectrum image obtained by the rotational temperature spectrum measurement subsystem in step 1 adopts a multi-parameter adaptive iterative inversion algorithm, which compares and calculates the synthetic spectrum of the standard reference at different temperatures in the forward simulation with the actual observed synthetic spectrum, calculates the minimum average difference between the two, and thus determines the actual observed temperature; The synthetic spectrum of the standard reference is obtained by simulation of a forward model, which includes an airglow radiation spectrum, atmospheric radiation transmission, an optical system submodule, and a CCD sensor module. The airglow radiation spectrum, atmospheric radiation transmission, and optical system submodules simulate the airglow radiation intensity received by the rotational temperature spectrum measurement subsystem, and the CCD sensor module performs photoelectric conversion to output a simulated image. Based on the center of the simulated image, the average value of all values ​​within each axisymmetric ring is calculated with a width of 1 bin, and then the values ​​are combined in sequence to obtain a synthetic spectrum of the standard reference for forward simulation; The simulated image is iteratively adjusted using five variable parameters: sky stray light, atmospheric temperature, filter temperature, optical system focal length, and synthetic spectral image modulation; The actually observed synthetic spectrum is obtained by performing dark noise removal, discrete bright spot removal, distorted image removal, circle center calculation, concentric circle slope calculation and image distortion correction on the original image obtained by the rotational temperature spectrum measurement subsystem.

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