Laser radar for atmospheric waveguide fast measurement
By combining differential absorption and hyperspectral resolution techniques of 822nm and 532nm lasers in lidar, the problems of system complexity and high cost in atmospheric waveguide measurement in existing technologies have been solved, and rapid and high-precision measurement of atmospheric waveguides has been achieved.
Patent Information
- Application Number
- CN202610320553.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-17
- Publication Date
- 2026-07-14
AI Technical Summary
Existing lidar technology suffers from problems such as high system complexity, high cost, difficulty in achieving stable all-weather and all-day detection, low accuracy, and difficulty in quantitative detection of single gases when measuring atmospheric waveguides. In particular, Raman scattering lidar has weak echo signals, and differential absorption lidar requires multiple discrete laser source combinations.
A single optical parametric oscillator and its frequency doubling module are used to generate 822nm and 532nm lasers. By combining differential absorption lidar and hyperspectral resolution lidar technology, the integrated, rapid, and high-precision measurement of temperature and humidity profiles is achieved through optical path design.
This method enables simultaneous and coordinated detection of key atmospheric waveguide parameters, simplifies the system structure, reduces costs, and improves energy utilization efficiency and measurement accuracy.
Smart Images
Figure CN122386330A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of lidar technology, and in particular to a lidar for atmospheric waveguide measurement. Background Technology
[0002] Atmospheric waveguides are a special type of atmospheric refractive index stratification structure that can cause abnormal propagation of electromagnetic waves, significantly affecting the operating range and performance of electronic systems such as radar and communication. Atmospheric waveguides can be measured indirectly by measuring atmospheric temperature and humidity data. Atmospheric temperature and humidity remote sensing equipment generally includes passive and active remote sensing devices. Passive remote sensing devices can receive the radiation signals from the atmosphere itself to retrieve atmospheric temperature and humidity. However, these devices rely on solar radiation and are significantly affected by day-night cycles, clouds, and aerosols, making stable, all-weather, and 24 / 7 detection impossible. Furthermore, their detection accuracy is relatively low, making it difficult to accurately obtain the stratification details of atmospheric waveguides. Active lidar technology, on the other hand, offers advantages in measuring atmospheric temperature and humidity, including continuous detection, high accuracy, and high spatiotemporal resolution. Currently, there are two main types: Raman scattering lidar and differential absorption lidar. Raman lidar can simultaneously measure atmospheric temperature and humidity profiles and has a relatively simple system structure. However, due to the small scattering cross-section of Raman scattering, the echo signal is weak, requiring a long integration time, making it unsuitable for long-distance spaceborne applications. Differential absorption lidar is suitable for long-range spaceborne applications. This technology has stringent requirements for laser linewidth and spectral purity, demanding narrow linewidth and high spectral purity as core indicators. Limited by this technical characteristic, traditional differential absorption lidar can typically only achieve quantitative detection of a single gas. To simultaneously retrieve atmospheric temperature and humidity, it is often necessary to measure the concentrations of multiple characteristic gases simultaneously. This necessitates constructing a detection system using a combination of multiple discrete laser sources, significantly increasing the system's structural complexity, hardware costs, and integration difficulties. Summary of the Invention
[0003] This invention addresses the aforementioned technical bottlenecks and application challenges of existing active detection lidar by proposing a lidar for atmospheric waveguide measurement. It utilizes a single optical parametric oscillator and its frequency doubling module to simultaneously generate an 822nm laser for humidity measurement and a 532nm laser for temperature measurement. At the receiving end, through a corresponding optical path design, it integrates differential absorption lidar technology and hyperspectral resolution lidar technology, achieving integrated, rapid, and high-precision measurement of key atmospheric waveguide parameters—temperature and humidity profiles. The technical solution of this invention is as follows: A lidar technology for rapid measurement of atmospheric waveguides includes a laser emitting module, an echo receiving module, and a data acquisition and processing module, characterized in that... The laser emitting module includes: an 822nm in-line seed laser, an 822nm offline seed laser, a 1064nm pump laser, an optical parametric oscillator, a laser frequency-locking module, an acousto-optic modulator, a frequency doubling module, and emitting optical components. The 822nm in-line and offline seed lasers output seed light, which is injected into the optical parametric oscillator as the starting seed light. The 1064nm pump light output from the 1064nm pump laser is injected into the optical parametric oscillator as the pump source. The remaining 1064nm seed light after passing through the optical parametric oscillator is converted into a 532nm pulsed laser output through the acousto-optic modulator and the frequency doubling module, and then enters the atmosphere via the optical emitting components. The output terminal of the laser frequency-locking module is connected to the second input terminal of the optical parametric oscillator, and the required frequency is locked by dynamically adjusting the cavity length. The 822nm pulsed light generated by the optical parametric oscillator enters the optical emitting components and then enters the atmosphere.
[0004] The echo receiving module includes a receiving telescope, a beam splitter, a reflector, a filter, a lens, a FP interferometer, a polarizing beam splitter prism, an iodine molecule absorption cell, a Fizeau interferometer, and a photodetector. The laser echo signal passing through the atmosphere enters the optical receiving telescope for reception. The beam splitter divides the laser echo signal into two paths: an 822nm signal light and a 532nm signal light. The 822nm signal light passes through the filter and lens and is then received by the photodetector. The 532nm echo signal, after being reflected by the reflector, passes through the filter and FP interferometer and is then split into vertically polarized light and parallel polarized light by the polarizing beam splitter prism. The vertically polarized 532nm light passes through the lens and is received by the photodetector. The parallel polarized light is split into two parts by the beam splitter: one part passes through the iodine molecule absorption cell, the Fizeau interferometer, and the lens and is received by the photodetector; the other part passes through the lens and is also received by the photodetector.
[0005] The data acquisition and processing module is connected to the receiving module and is responsible for subsequent data acquisition and processing of the lidar system.
[0006] The 822nm online seed laser and the 822nm offline seed laser need to output two seed lights with very small wavelength differences, located at the 822nm absorption peak and absorption valley of water vapor, respectively. The seed light has high frequency stability and low power continuous wave.
[0007] The optical parametric oscillator, together with the seed laser and the 1064nm pump laser, constitutes a seed-injected optical parametric oscillator, generating a narrow-linewidth amplified pulsed laser.
[0008] The aforementioned acousto-optic modulator and frequency doubling module enable the 1064nm seed light to be frequency-doubled into 532nm pulsed light output.
[0009] The beam splitter splits the 822nm band signal and the 532nm band signal in the echo signal into two paths, corresponding to the water vapor and temperature detection channels, respectively.
[0010] The Fizeau interferometer described above can perform high-precision wavelength dispersion and phase modulation on 532nm parallel polarized light passing through an iodine molecule absorption cell, converting the wavelength shift of the incident light into the displacement of the interference fringes. Combined with the interference signal collected by the photodetector, it can achieve fine resolution of the wavelength of the 532nm laser echo.
[0011] The data acquisition and processing module includes a data acquisition card and a computer. The computer has pre-installed algorithms for executing the following inversion program: Based on the echo signals of 822nm online and offline wavelengths collected by the humidity detection channel, the water vapor concentration profile is inverted based on the differential absorption principle, and then the humidity profile is obtained. Based on the interference fringe displacement acquired by the high-spectral-resolution temperature detection channel, and calibrated by combining the signals from the Mie scattering signal detection channel and the third photodetector, the atmospheric temperature profile is obtained by optimally fitting the measured spectral characteristics with the theoretical Rayleigh-Brillouin scattering spectral model. Based on the humidity profile, temperature profile and pressure profile obtained from the inversion, the atmospheric refractive index profile is calculated, and the existence of the atmospheric waveguide and its stratification parameters are determined.
[0012] Compared with the prior art, the advantages of the present invention are as follows: 1. An active detection method is adopted: Differential absorption lidar technology is integrated with Fizeau interferometer-based hyperspectral resolution lidar technology into a single system. Humidity is measured using an 822nm laser generated by the same pump source and optical parametric oscillator, and temperature is measured using a 532nm laser generated by frequency doubling of its remaining energy. This achieves simultaneous and coordinated detection of two key parameters of the atmospheric waveguide.
[0013] 2. By using a seed-injected optical parametric oscillator, not only was a high-frequency stable, narrow-linewidth 822nm pulsed laser obtained to meet the requirements of differential absorption detection, but the remaining 1064nm energy from the OPO process was also utilized and converted into a 532nm laser via a frequency doubling module, serving as a light source for temperature detection. This design achieves multi-wavelength, multi-purpose laser output excited by a single master laser, greatly simplifying the system structure, reducing costs, and improving energy utilization efficiency.
[0014] 3. In the 532nm temperature detection channel, a high-spectral-resolution detection optical path based on an iodine molecule absorption cell and a Fizeau interferometer was constructed. The strong background noise in the aerosol Mie scattering signal was filtered out by the iodine molecule absorption cell. The Fizeau interferometer was used to convert the slight Doppler broadening (i.e., temperature information) of the atmospheric molecule Rayleigh scattering signal into high-precision interference fringe shifts, which were received by a photodetector. Simultaneously, by setting up both a Mie scattering signal detection channel (photodetector) and a direct detection channel (photodetector), rich reference information was provided for data inversion, ensuring high accuracy and fast response in temperature inversion. Attached Figure Description
[0015] Figure 1 This is an overall structural block diagram of the lidar system for atmospheric waveguide measurement according to the present invention.
[0016] Figure 2 This is the 822nm water vapor absorption line diagram upon which this invention is based. Detailed Implementation
[0017] The present invention will be further described below with reference to examples and accompanying drawings, but this should not be construed as limiting the scope of protection of the present invention.
[0018] Please see Figure 1 , Figure 1 The figure shows the overall structural block diagram of the lidar system for atmospheric waveguide measurement of the present invention. As shown in the figure, the lidar system of the present invention mainly consists of three parts: a laser emitting module, an echo receiving module, and a data acquisition and processing module.
[0019] The laser emission module includes: an 822nm in-line seed laser 1, an 822nm offline seed laser 2, a 1064nm pump laser 3, a laser frequency locking module 5, an optical parametric oscillator (OPO) 4, an acousto-optic modulator (AOM) 6, a frequency doubling module 7, and emission optics components 8.
[0020] The echo receiving module includes an optical receiving telescope 9, a first beam splitter 10, a second beam splitter 20, a reflector 14, a first filter 11, a second filter 15, a first lens 12, a second lens 18, a third lens 21, a fourth lens 25, an FP filter 16, a polarizing beam splitter 17, an iodine molecule absorption cell 23, a Fizeau interferometer 24, and a first photodetector 13, a second photodetector 19, a third photodetector 22, and a fourth photodetector 26.
[0021] The data acquisition and processing module 27 includes a high-speed data acquisition card, a timing controller, and an industrial computer. This module is connected to the output terminals of the first photodetector 13, the second photodetector 19, the third photodetector 22, and the fourth photodetector 26, and is responsible for amplifying, filtering, converting analog to digital, and acquiring the weak electrical signals output by the photodetectors.
[0022] The 822nm online seed laser 1 and 822nm offline seed laser 2 are narrow-linewidth, high-frequency-stability continuous-wave lasers. They respectively generate wavelengths located at the 822nm absorption peak and absorption valley of water vapor (e.g., Figure 2 The two seed beams are injected into the optical parametric oscillator (OPO) via an optical fiber or spatial optical path, serving as seed sources for OPO oscillation and locking the accuracy and narrow linewidth characteristics of the OPO output wavelength.
[0023] The 1064nm pump laser 3 is injected into the optical parametric oscillator 4 as pump light, providing the necessary pump energy for the gain medium (such as a BBO crystal) of the OPO. The laser frequency-locking module 5 monitors the output wavelength of the OPO and dynamically adjusts the cavity length of the OPO's resonant cavity to ensure that its resonant frequency is always locked with the frequency of the injected seed light, thereby obtaining a high-frequency-stability 822nm pulsed laser output. This 822nm pulsed laser is guided to the emitting optical component 8.
[0024] In the optical parametric oscillator 4, while the pump light interacts with the seed light to generate an 822nm signal light, a portion of 1064nm seed light remains unconverted. This remaining 1064nm laser light enters the acousto-optic modulator 6, where it is modulated into a pulsed light synchronized with the 822nm pulsed laser, and then enters the frequency doubling module 7. The frequency doubling module 7 contains a phase-matched nonlinear crystal (such as an LBO crystal) to double the frequency of the 1064nm pulsed laser light, generating a 532nm pulsed laser light. This 532nm pulsed laser light is also guided to the transmitting optical component 8.
[0025] The transmitting optical component 8 typically consists of a collimating lens, a beam expander, etc., used to shape, collimate, and expand the received 822nm and 532nm pulsed laser beams to compress the beam divergence angle, and then emit them into the atmosphere in a coaxial or parallel manner. The 822nm beam is used for humidity detection, and the 532nm beam is used for temperature detection.
[0026] The laser echo signal after passing through the atmosphere is collected by the optical receiving telescope 9. The collected signal light is first incident on the first beam splitter 10, which has wavelength selective characteristics, such as high reflection of 822nm light and high transmission of 532nm light, thereby splitting the echo signal into two paths: one path is the 822nm signal light, which enters the humidity detection channel; the other path is the 532nm signal light, which enters the temperature detection channel.
[0027] For the humidity detection channel: the 822nm signal light passes sequentially through filter 11 and first lens 12. The first filter 11 is a narrowband interference filter with a center wavelength near 822nm, used to suppress solar background noise. The filtered and focused signal light is received by the first photodetector 13 and converted into an electrical signal. The first photodetector 13 can be a high-sensitivity APD detector. This channel receives the backscattered signal intensity P corresponding to the online and offline wavelengths of 822nm. on and P off .
[0028] For the temperature detection channel: the 532nm signal light, after being reflected by mirror 14, passes through the second filter 15 and the FP interferometer 16, and is then split into vertically polarized light and parallel polarized light by polarizing beam splitter 17. The vertically polarized light is focused by the second lens 18 and received by photodetector 19. The parallel polarized light is split into two parts by the second beam splitter 20. One part passes through iodine molecular absorption cell 23, which is filled with stable iodine vapor. Its absorption spectrum has a series of fine absorption peaks near 532nm, which can efficiently absorb the wide-bandwidth aerosol Mie scattering signal, while only allowing the extremely narrow-bandwidth molecular Rayleigh scattering signal to pass through. The transmitted Rayleigh scattering signal enters the Fizeau interferometer 24. The wavelength of the Rayleigh scattering signal undergoes a slight shift due to Doppler broadening caused by changes in atmospheric temperature. This shift is converted into a shift in the position of the interference fringes by the Fizeau interferometer 24. The signal light carrying the fringe shift information is imaged onto photodetector 26 by the fourth lens 25, and the photodetector 26 acquires the interference fringe image. The other part is received by the photodetector 22 after passing through the second lens 21.
[0029] The data acquisition and processing module 27 includes a data acquisition card, a computer, etc., and is connected to the output terminals of the first photodetector 13, the second photodetector 19, the third photodetector 22, and the fourth photodetector 26. It is responsible for amplifying, filtering, analog-to-digital conversion, and data acquisition of the weak electrical signals output by the photodetectors.
[0030] Example 1: The optical parametric oscillator 4 uses a BBO crystal. An optical parametric amplifier (OPA) module is added after the OPO module to meet the high-energy output requirements. The remaining 1064nm laser light after passing through the optical parametric oscillator 4 is converted into 532nm pulsed light output after passing through a frequency doubling crystal 7 using an LBO. The transmitting optical assembly 8 consists of a collimating lens, a beam expander, etc. The optical receiving telescope assembly 9 uses a Cassegrain telescope; the first photodetector 14 is an APD detector, and the second photodetector 19, the third photodetector 22, and the fourth photodetector 26 are PMT detectors.
[0031] The specific process of a lidar system for rapid atmospheric waveguide measurement according to the present invention is as follows: The 822nm online seed laser and the 822nm offline seed laser output seed light, which is injected into the optical parametric oscillator as the starting seed light. The 1064nm pump light output from the 1064nm pump laser is injected into the optical parametric oscillator as the pump source, and the optical parametric oscillator generates 822nm pulsed light which is then output into the atmosphere. The remaining 1064nm seed light is converted into 532nm pulsed laser output through an acousto-optic modulator and a frequency doubling module, and then enters the atmosphere through the optical emission assembly.
[0032] The echo signal enters the lidar via the optical receiving telescope assembly 10. For the 822nm water vapor detection channel, it is necessary to receive atmospheric backscattered signals P from different positions along the laser path. on P off According to the principle of differential absorption, the concentration of water vapor at different locations along the path is... ,in The absorption cross section of water vapor at the online and offline locations (the absorption interface is calculated based on the temperature, humidity and pressure profiles at the measured locations and the line type parameters in the HITRAN database). , R1 and R2 are the distances between any two points on the laser path and the radar. For the 532nm temperature detection channel, the echo signal is... ,in, The emission power of the laser. For the system's optical efficiency; The area of the receiving telescope; The speed of light; The pulse width of the laser; The geometric overlap factor of the lidar system; To detect the distance from the target to the lidar system; is the backscattering coefficient of the aerosol; The backscattering coefficient of atmospheric molecules; The extinction coefficient of the aerosol; The extinction coefficient of atmospheric molecules is denoted as . The received molecular and aerosol echo signals are distributed onto their respective scattering spectra, where the Rayleigh-Brillouin scattering spectrum of molecules is calculated using a model. The Levenberg-Marquardt (LM) algorithm is used to optimize the fit between the actual detected scattering spectrum and the theoretical spectrum, thereby retrieving the atmospheric temperature profile.
[0033] After obtaining the temperature and humidity profiles, and combining them with the pressure profile from meteorological reanalysis data, the formula for calculating the atmospheric refractive index is: Where P is atmospheric pressure, T is atmospheric temperature, and e is water vapor pressure. The refractive index modulus M is usually used to simplify calculations, defined as... The refractive index condition for generating atmospheric waveguides is Where Re is the Earth's radius. The term is the Earth curvature correction term, which is usually approximated as -0.157 N-unit / m.
[0034] Example 2 This embodiment optimizes the selection and parameters of key components based on Embodiment 1. To meet the high-energy requirements of long-range spaceborne or airborne detection, one or more stages of optical parametric amplifiers (OPA) can be added after the optical parametric oscillator 4 and before the transmitting optical component 8. The 822nm seed light generated by the optical parametric oscillator 4 is injected as the signal light into the OPA, and a portion of the energy from the 1064nm pump laser 3 is used as the pump light for the OPA, amplifying the power of the 822nm seed light to obtain a higher-energy 822nm pulsed laser output, thereby enhancing the echo signal intensity and improving the detection range and signal-to-noise ratio. Correspondingly, the remaining 1064nm light energy is also higher, and after frequency doubling, a stronger 532nm laser output can be obtained.
[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A lidar for measuring atmospheric waveguide velocity, characterized in that, It includes a laser emitting module, an echo receiving module, and a data acquisition and processing module; The laser emitting module includes: an 822nm online seed laser (1), an 822nm offline seed laser (2), a 1064nm pump laser (3), an optical parametric oscillator (4), a laser frequency locking module (5), an acousto-optic modulator (6), a frequency doubling module (7), and emitting optical components (8). The optical output terminals of the 822nm online seed laser (1) and the 822nm offline seed laser (2) are both connected to the first input terminal of the optical parametric oscillator (4) for injecting seed light into the optical parametric oscillator (4). The optical output terminal of the 1064nm pump laser (3) is connected to the second input terminal of the optical parametric oscillator (4) for injecting pump light into the optical parametric oscillator (4). The control terminal of the laser frequency locking module (5) is connected to the third input terminal of the optical parametric oscillator (4) for locking the optical parametric oscillator (4) by dynamically adjusting the cavity length. The output frequency; the first optical output end of the optical parametric oscillator (4) is connected to the emitting optical component (8) to output the generated 822nm pulsed laser to the emitting optical component (8); its second optical output end is connected to the emitting optical component (8) in sequence through the acousto-optic modulator (6) and the frequency doubling module (7) to convert the remaining 1064nm laser in the optical parametric oscillator (4) into a 532nm pulsed laser and output it to the emitting optical component (8); the emitting optical component (8) is used to shape the received 822nm pulsed laser and 532nm pulsed laser and emit them into the atmosphere; The echo receiving module includes a receiving telescope (9), a first beam splitter (10), a second beam splitter (20), a reflector (14), a first filter (11), a second filter (15), a first lens (12), a second lens (18), a third lens (21) and a fourth lens (25), a FP interferometer (16), a polarizing beam splitter (17), an iodine molecule absorption cell (23), a Fizeau interferometer (24), and a first photodetector (13), a second photodetector (19), a third photodetector (22), and a fourth photodetector (26). The receiving telescope (9) is used to collect atmospheric backscattered signals. Its light output end is opposite to the incident surface of the first beam splitter (10). The first beam splitter (10) is used to separate the received signal light into two paths: 822nm band signal light and 532nm band signal light. The 822nm signal light is received by the first photodetector (13) after passing through the first filter (11) and the first lens (12) to form a humidity detection channel; The 532nm echo signal is reflected by the mirror (14), and after passing through the second filter (15) and the FP interferometer (16), it is split into vertically polarized light and parallel polarized light by the polarizing beam splitter (17). The vertically polarized light is received by the photodetector (19) after passing through the second lens (18), forming a Mie scattering signal detection channel. The parallel polarized light is split into two parts by the second beam splitter (20). One part passes through the iodine molecule absorption cell (23), the Fizeau interferometer (24), and the fourth lens (25) and is received by the photodetector (26). The other part passes through the third lens (21) and is received by the third photodetector (22). The iodine molecule absorption cell (23), the Fizeau interferometer (24), the fourth lens (25), and the fourth photodetector (26) together constitute a high-spectral-resolution temperature detection channel. The input terminal of the data acquisition and processing module (27) is electrically connected to the output terminals of the first photodetector (13), the second photodetector (19), the third photodetector (22) and the fourth photodetector (26), respectively, to acquire and process the signals, invert the atmospheric temperature profile and humidity profile, and then calculate the atmospheric refractive index profile and identify the atmospheric waveguide.
2. The lidar technology for atmospheric waveguide measurement according to claim 1, characterized in that, The 822nm online seed laser (1) and the 822nm offline seed laser (2) are both continuous wave lasers with narrow linewidth and high frequency stability, and their output wavelengths are located at the 822nm absorption peak and absorption valley of water vapor, respectively.
3. The lidar technology for atmospheric waveguide measurement according to claim 1, characterized in that, The optical parametric oscillator (4), together with the 822nm online seed laser (1), the 822nm offline seed laser (2) and the 1064nm pump laser (3), constitutes a seed-injected optical parametric oscillator, which is used to generate a narrow linewidth, high frequency stability 822nm pulsed laser.
4. The lidar technology for atmospheric waveguide measurement according to claim 1, characterized in that, The frequency multiplier module (7) is a frequency multiplier containing a nonlinear crystal, used to convert 1064nm laser into 532nm laser.
5. The lidar technology for atmospheric waveguide measurement according to claim 1, characterized in that, The laser emitting module further includes an optical parametric amplifier. The signal light input terminal of the optical parametric amplifier is connected to the first optical output terminal of the optical parametric oscillator (4), the pump light input terminal is connected to the other output terminal of the 1064nm pump laser (3), and the optical output terminal is connected to the emitting optical component (8) for power amplification of the 822nm pulsed laser.
6. The lidar technology for atmospheric waveguide measurement according to claim 1, characterized in that, The beam splitter (10) splits the 822nm band signal and the 532nm band signal in the echo signal into two paths, which correspond to the humidity and temperature detection channels, respectively.
7. The lidar technology for rapid measurement of atmospheric waveguides according to claim 1, characterized in that, The Fizeau interferometer is an ultra-narrowband filter that can perform high-precision wavelength dispersion and phase modulation on 532nm parallel polarized light passing through the iodine molecule absorption cell. It converts the wavelength shift of the incident light into the displacement of the interference fringes. Combined with the interference signal collected by the photodetector (26), it can achieve fine resolution of the wavelength of the 532nm laser echo.
8. The lidar technology for rapid measurement of atmospheric waveguides according to claim 1, characterized in that, The iodine molecule absorption cell (23) is filled with stable iodine vapor, whose absorption spectrum is matched with the 532nm laser. It is used to absorb the wide bandwidth of aerosol Mie scattering signal and transmit the extremely narrow bandwidth of atmospheric molecule Rayleigh scattering signal.
9. The lidar technology for rapid measurement of atmospheric waveguides according to claim 1, characterized in that, The Fizeau interferometer (24) is a non-scanning high spectral resolution dispersive element used to accurately convert the wavelength shift of the Rayleigh scattering signal into the spatial displacement of the interference fringes, which is then collected by the fourth photodetector (26).
10. A lidar for rapid measurement of atmospheric waveguides according to claim 1, characterized in that, The data acquisition and processing module (27) includes a data acquisition card and a computer. The computer has a pre-installed algorithm for executing the following inversion procedure: Based on the echo signals of 822nm online and offline wavelengths collected by the humidity detection channel, the water vapor concentration profile is inverted based on the differential absorption principle, and then the humidity profile is obtained. Based on the interference fringe displacement collected by the high-spectral-resolution temperature detection channel, and combined with the signals from the Mie scattering signal detection channel and the third photodetector (22), the atmospheric temperature profile is obtained by optimally fitting the measured spectral characteristics with the theoretical Rayleigh-Brillouin scattering spectral model. Based on the humidity profile, temperature profile and pressure profile obtained from the inversion, the atmospheric refractive index profile is calculated, and the existence of the atmospheric waveguide and its stratification parameters are determined.