System and method for synchronous detection of atmospheric data in same path

Abstract

The present invention belongs to the technical field of LiDARs, and particularly relates to a system and method for synchronous detection of atmospheric data in the same path. The detection system comprises a transmitting unit, a receiving unit and a data processing unit, wherein the transmitting unit comprises a plurality of laser devices, and is used for synchronously transmitting laser having different wavelengths in a common path; the receiving unit comprises a receiving telescope, which is symmetrically provided with a plurality of sub-apertures used for receiving echo signals that are generated after the laser having different wavelengths interacts with the atmosphere; and the data processing unit is used for calculating atmospheric data parameters by means of the echo signals. By means of the present invention, synchronous detection of a plurality of atmospheric data parameters in the same path can be implemented.

Description

Atmospheric data same-path synchronous detection system and method Technical Field

[0001] The present invention belongs to the technical field of laser radar, and in particular relates to a system and method for synchronous detection of atmospheric data on the same path. Background Art

[0002] The comprehensive detection of multiple atmospheric parameters is crucial for applications such as laser atmospheric transmission, environmental monitoring, and aerospace. During atmospheric transmission, atmospheric transmittance characterizes the laser's energy attenuation. Atmospheric turbulence influences the laser's spatial phase distribution, intensity fluctuations, and beam drift. Atmospheric winds influence the distribution of the medium in space and significantly impact thermal blooming in nonlinear optics. These three parameters interact with each other and contribute to the laser's atmospheric transmission. Therefore, the comprehensive detection of atmospheric transmittance, atmospheric turbulence, and winds is crucial.

[0003] LiDAR has received widespread attention in atmospheric detection due to its high temporal and spatial resolution, real-time and continuous measurement characteristics, and its ability to achieve single-path detection.

[0004] When LiDAR detects atmospheric transmittance, it receives backscattered echo signals, collects data, and inverts them to obtain atmospheric transmittance information. LiDAR can measure vertical extinction profiles, but its ability to measure atmospheric transmittance using slant paths is limited.

[0005] For wind field detection, lidar can detect wind speed, turbulence, and real-time wind field measurements by measuring the backscatter of small amounts of naturally occurring particles in the atmosphere. There are generally two detection mechanisms: incoherent Doppler wind lidar and coherent Doppler wind lidar. Incoherent Doppler wind lidar systems can detect atmospheric wind fields above the troposphere and stratosphere, but they require a high-energy laser and frequency stabilization. The Doppler frequency shift is obtained by scanning the transmittance curve with a frequency discriminator. The subsequent optical path is complex, and the system size is relatively large. Coherent wind lidar systems, benefiting from the advancement of all-fiber communications and related products, are compact, stable, and easy to integrate.

[0006] The atmospheric coherence length (ACL) not only characterizes the intensity of turbulence but also its phase fluctuations. Therefore, accurately acquiring this information to characterize atmospheric turbulence is crucial. To achieve path-based ACL detection, lidar (LiDAR) actively emits laser light, focusing it to form a Rayleigh beacon. The beacon is imaged in an optical system, and the ACL is inverted from the center-of-mass jitter variance of the two light spots. While studying optical transfer functions, Fried established a relationship between the ACL and the atmospheric refractive index structure constant under weak fluctuation conditions. Traditional turbulence lidar detects vertically, and acquiring r0 at different altitudes requires focusing the beacon at different altitudes, which is quite challenging.

[0007] Currently, the method for detecting these various atmospheric parameters (atmospheric transmittance, turbulence characteristics, and wind field) is generally to use multiple different types of lidars for simultaneous detection. However, this requires the simultaneous operation of multiple lasers, telescopes, and signal detection equipment. This is technically complex and difficult to detect, resulting in low operational reliability. Multiple lidar systems cannot emit lasers synchronously, and the multiple laser beams will deviate spatially, resulting in temporal and spatial inconsistencies in the return signals from the multiple lidars. This makes simultaneous, common-path detection of atmospheric transmittance, turbulence characteristics, and wind field impossible.

[0008] Summary of the Invention

[0009] In order to solve the above problems, the present invention discloses an atmospheric data same-path synchronous detection system, wherein the detection system includes a transmitting unit, a receiving unit and a data processing unit;

[0010] The transmitting unit includes multiple lasers for synchronously transmitting lasers of different wavelengths in a common path;

[0011] The receiving unit includes a receiving telescope, wherein the receiving telescope is symmetrically provided with a plurality of sub-pupils for receiving echo signals after the lasers of different wavelengths interact with the atmosphere;

[0012] The data processing unit is used to calculate atmospheric data parameters through the echo signal.

[0013] Further, the laser includes a first laser and a second laser;

[0014] The first laser is fixed above the receiving telescope and is used to simultaneously transmit a first fundamental frequency laser and a corresponding doubled frequency laser of a first set wavelength in the same path. A total reflection mirror and a beam expander are sequentially installed at the front end of the first laser.

[0015] The second laser is installed as a whole below the receiving telescope and is used for emitting laser light of a second fundamental frequency with a second set wavelength in a synchronized manner with the first laser.

[0016] Furthermore, the emission optical path of the second laser adopts off-axis emission and is co-located with the receiving optical path;

[0017] The outgoing laser beam is kept parallel to the optical axis of the receiving telescope.

[0018] Furthermore, the outgoing laser of the first fundamental frequency is emitted by beam expansion and collimation;

[0019] The corresponding output laser of the doubled frequency laser is emitted by beam expansion and focusing.

[0020] Furthermore, the receiving unit as a whole is a Cassegrain reflective structure, with an upper sub-pupil, a lower sub-pupil, a left sub-pupil and a right sub-pupil symmetrically arranged up and down and left and right, and the distance between the two sub-pupils is greater than 2 times the diameter of the sub-pupil.

[0021] Furthermore, on the plane of the four sub-pupils, a left exit hole and a right exit hole are correspondingly provided on the left and right sides. The left exit hole emits an exit laser of the first fundamental frequency, and the right exit hole emits a corresponding doubled frequency laser. The right exit hole is arranged on a midpoint line perpendicular to the midpoint line connecting the left and right sub-pupils.

[0022] Furthermore, the data processing unit includes an atmospheric transmittance detection channel, an atmospheric coherence length detection channel and an atmospheric wind field detection channel;

[0023] The atmospheric transmittance detection channel includes a first APD detector and a first data collector, wherein the first APD detector is used to convert the backscattered spatial light signal generated by the interaction of the first fundamental frequency laser with atmospheric molecules and aerosol particles into an electrical signal, and the first data collector is used to collect the electrical signal;

[0024] The atmospheric coherence length detection channel includes a reflector, a second filter and a second ICCD detector, wherein the reflector and the second filter are used to send the received echo signal to the target surface of the second ICCD detector, and the second ICCD detector is used to convert the echo signal into a digital signal;

[0025] The atmospheric wind field detection channel includes a circulator, a fiber optic coupler, a balanced detector and a second data collector. The circulator is used to output the echo signal to the fiber optic coupler, and the fiber optic coupler is used to split the echo signal after beating with another local oscillator light. The balanced detector is used to convert the optical signal into an electrical signal, and the second data collector is used to convert the electrical signal into a digital signal.

[0026] Furthermore, the detection system further includes a computing unit;

[0027] When the calculation unit receives and processes the data output from the atmospheric transmittance detection channel, the calculation unit obtains the data collector and calculates the atmospheric transmittance; when receiving and processing the digital signal transmitted by the atmospheric coherence length detection channel, the calculation unit can realize the atmospheric coherence length measurement. When receiving and processing the digital signal from the atmospheric wind field detection channel, the digital signal is transformed by FFT to obtain the signal power spectrum, and then the output wind speed is calculated using the inversion formula.

[0028] Furthermore, the detection system also includes a scanning platform and a control unit; the scanning platform includes a main control board and a driver; the driver is used to control the scanning parameters of the transmitting unit and the receiving unit according to the instructions of the main control board, wherein the scanning parameters include azimuth, pitch angle, speed and step size;

[0029] The control unit is used to simultaneously trigger multiple lasers to generate laser pulses, and synchronously trigger the atmospheric transmittance detection channel, the atmospheric coherence length detection channel and the atmospheric wind field detection channel to perform synchronous common path data acquisition, storage and inversion.

[0030] Another embodiment of the present invention further discloses a method for synchronous detection of atmospheric data on the same path, the detection method comprising the following steps:

[0031] Use multiple lasers to synchronously emit lasers of different wavelengths on the same path;

[0032] Using a receiving telescope to receive echo signals after the interaction of lasers of different wavelengths with the atmosphere, wherein the receiving telescope is symmetrically provided with a plurality of sub-pupils;

[0033] The atmospheric data parameters are calculated respectively through the received echo signals.

[0034] The present invention can realize synchronous and same-path detection of multiple atmospheric data parameters.

[0035] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] FIG1 shows a schematic diagram of a transmitting unit in an atmospheric data same-path synchronous detection system according to an embodiment of the present invention;

[0038] FIG2 is a schematic diagram showing a receiving unit and a data processing unit in an atmospheric data same-path synchronous detection system according to an embodiment of the present invention;

[0039] FIG3 shows a schematic structural diagram of an atmospheric data same-path synchronous detection system according to an embodiment of the present invention.

[0040] In the figure: 101, first laser; 102, first total reflection mirror; 103, first beam expander; 104, Second total reflection mirror; 105, third total reflection mirror; 106, second beam expander; 107, fourth total reflection mirror; 108, left exit aperture; 109, right exit aperture; 111, second laser; 2, receiving unit; 20, receiving telescope; 201, sub-pupil; 21, folding mirror; 22, second filter; 23, beam splitter; 24, pinhole aperture; 25, first filter; 26, converging lens; 3, data processing unit; 31, atmospheric transmittance detection channel; 311, first APD detector; 312, first data collector; 32, atmospheric coherence length detection channel; 321, second ICCD detector; 33, atmospheric wind field detection channel; 331, circulator; 332, fiber optic coupler; 333, balance detector; 334, second data collector; 4, computing unit. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0042] The present invention discloses an atmospheric data same-path synchronous detection system, as shown in FIG1-3 , the detection system includes a transmitting unit 1 , a receiving unit 2 and a data processing unit 3 .

[0043] The transmitting unit 1 includes multiple lasers for synchronously transmitting lasers of different wavelengths in a common path. In this embodiment, two lasers are taken as an example.

[0044] The receiving unit 2 includes a receiving telescope 20, wherein the receiving telescope 20 is symmetrically provided with a plurality of sub-pupils 201 for receiving echo signals after the interaction of lasers of different wavelengths with the atmosphere;

[0045] The data processing unit 3 is used to calculate atmospheric data parameters through the echo signal.

[0046] The transmitting unit 1, the receiving unit 2 and the data processing unit 3 are described in detail below.

[0047] Transmitter unit 1

[0048] The two lasers in the transmitting unit 1 synchronously transmit laser beams of different wavelengths along the same path. The laser beams of different wavelengths interact with particles in the atmosphere to produce different echo signals. Since the receiving telescope 20 is provided with multiple sub-pupils 201, different sub-pupils 201 receive different echo signals. After receiving different echo signals, different sub-pupils 201 send the echo signals to the data processing unit 3. The data processing unit 3 uses different processing methods based on the different echo signals to ultimately obtain a variety of atmospheric data parameters. In this embodiment, the two lasers in the transmitting unit 1 transmit synchronously along the same path, and different sub-pupils 201 of the receiving telescope 20 receive the echo signals at the same time. In addition, the multiple detection channels of the data processing unit 3 simultaneously process the echo signals to obtain atmospheric data parameters. It can be seen that this embodiment can achieve synchronous detection of atmospheric data parameters along the same path, ensuring that the various atmospheric parameters at the same time are obtained to the greatest extent.

[0049] The two lasers are a first laser 101 and a second laser 111. The first laser 101 is mounted above the receiving telescope 20 and is used to simultaneously and co-pathways emit a first fundamental frequency laser beam and a corresponding doubled frequency laser beam at a first set wavelength. The laser output end of the first laser 101 is sequentially mounted with multiple total reflection mirrors and a beam expander. Specifically, in the optical path of the first fundamental frequency, the laser beam emitted by the first laser 101 passes through multiple total reflection mirrors and the first beam expander 103, outputting a first fundamental frequency beam beam at the first set wavelength. The second beam expander 106 has a fixed magnification and is used for beam expansion and collimation. In the optical path of the doubled frequency beam, the laser beam emitted by the first laser 101 passes through multiple total reflection mirrors and the first beam expander 103. The second beam expander 106 is a spirally adjustable beam expander that is used for beam expansion and focusing, outputting a doubled frequency beam beam at the first set wavelength. The second laser 111 is mounted entirely below the receiving telescope 20 and is used to synchronously and collimate the laser beam emitted by the first laser 101 at the second set wavelength.

[0050] Exemplarily, the first laser 101 is a seed-injection-stabilized Nd:YAG laser equipped with power and temperature control, and the second laser 111 is a pulsed erbium-doped fiber laser. The Nd:YAG laser simultaneously emits laser light at a fundamental frequency of 1064 nm and a second harmonic of 532 nm; the pulsed erbium-doped fiber laser emits laser light at a collimated frequency of 1550 nm.

[0051] Specifically, to ensure that the pulsed erbium-doped fiber laser and the Nd:YAG laser are synchronized and transmit in parallel, the pulsed erbium-doped fiber laser uses an off-axis transmission path. To ensure that the receiving telescope 20 can receive more echo signals, the outgoing laser is parallel to the optical axis of the receiving telescope 20.

[0052] For example, an Nd:YAG laser simultaneously emits a 1064nm fundamental frequency and a 532nm doubled frequency laser. After the two laser beams are expanded by a total reflection mirror and then beam-expanded by a beam expander, the 1064nm fundamental frequency laser is designed to detect atmospheric transmittance, ensuring that the divergence angle of the emitted laser is less than 1 / 2 of the receiving field of view and achieving higher detection requirements. The design uses a 2x beam expansion collimated emission, compressing the divergence angle of the emitted laser to 0.25mrad. The 532nm laser is designed to detect the atmospheric coherence length using a 10x beam expansion focused emission. Exemplarily, as shown in FIG1 , for the two optical paths of the first laser 101, specifically: on the optical path of the first fundamental frequency, the 1064nm laser passes through the third total reflection mirror 105 and enters the second beam expander 106 for beam expansion, and is then vertically emitted into the atmosphere by the fourth total reflection mirror 107. The third total reflection mirror 105 is adjusted so that the laser completely enters the second beam expander 106 to achieve a 2x beam expansion of the laser and reduce the emission angle. The fourth total reflection mirror 107 is adjusted so that the emission optical axis is parallel to the main axis of the receiving telescope 20. In the optical path of the second harmonic of the first fundamental frequency, the total reflection mirrors include a first total reflection mirror 102 and a second total reflection mirror 104. The laser emitted by the first laser 101 passes through the first total reflection mirror 102 and enters the first beam expander 103 for beam expansion, and is then vertically emitted into the atmosphere by the second total reflection mirror 104. By adjusting the first reflector 102, the laser beam is completely directed into the first beam expander 103, thereby achieving a 10-fold beam expansion and reducing the emission angle. By adjusting the second total reflection mirror 104, the emission optical axis is parallel to the main axis of the receiving telescope 20. It is worth noting that the first total reflection mirror 102, the second total reflection mirror 104, the third total reflection mirror 105, and the fourth total reflection mirror 107 can be combined with multiple total reflection mirrors as needed. For example, to change the optical path, the first total reflection mirror 102 is composed of three total reflection mirrors with the same properties.

[0053] Exemplarily, the second laser 111 emits a 1550 nm wavelength which sequentially passes through the beam splitter 112, the acousto-optic modulator 113, the amplifier 114 and the circulator 331 and enters the receiving telescope 20 for transmission, and is co-located with the receiving optical path.

[0054] Receiving unit 2

[0055] Due to the large span of the three wavelengths being received, to ensure the reception of more echo signals, the receiving unit 2 utilizes a Cassegrain reflective structure. Four sub-pupils 201 are symmetrically arranged vertically and horizontally: upper, lower, left, and right. The spacing between sub-pupils 201 is greater than twice their diameter. Left and right exit apertures 108 and 109 are located on the planes of the four sub-pupils 201, respectively. Left exit aperture 108 emits laser light with a wavelength of 1064 nm, while right exit aperture 109 emits laser light with a wavelength of 532 nm. Right exit aperture 109 is positioned perpendicular to the midpoint of the line connecting the left and right sub-pupils.

[0056] Specifically, the upper sub-pupil is used to receive the backscattered spatial light signal generated by the interaction between the pulsed laser of the first fundamental frequency and the atmospheric molecules and aerosol particles, hereinafter referred to as the echo signal; the left sub-pupil and the right sub-pupil are used to receive the echo signal generated by the interaction between the second-harmonic frequency laser corresponding to the first fundamental frequency and the atmospheric molecules and aerosol particles; the lower sub-pupil is used to receive the echo signal carrying wind field information generated by the interaction between the pulsed laser of the second fundamental frequency and the atmosphere.

[0057] For example, the echo signal generated by the interaction of the 1064nm wavelength laser with atmospheric molecules and aerosol particles is received by the upper sub-pupil, which includes a primary mirror, a secondary mirror, a turning mirror, an aperture, an eyepiece, a filter and a converging lens arranged in sequence. The echo signal is finally detected by the APD (avalanche photodiode), and then the atmospheric transmittance information at different distances is obtained by the data processing unit in combination with the inversion algorithm. Wedge-shaped mirrors are placed at the left and right sub-pupils to receive the echo signal generated by the interaction of the 532nm wavelength laser with atmospheric molecules and aerosol particles, and separate the two light spots. The two light spot signals are then received respectively by the primary mirror and the secondary mirror of the Cassegrain system. The light spot signal passes through the subsequent optical path such as the reflector and the filter in sequence and is sent to the target surface of the intensified charge-coupled camera ICCD to realize imaging. Finally, the data processing unit measures the atmospheric coherence length based on the image. After the 1550nm laser light emitted by a pulsed erbium-doped fiber laser interacts with the atmosphere, the echo signal is received by the lower sub-pupil. It then passes through the primary mirror and reflector of the receiving telescope, then into the optical fiber, enabling atmospheric wind field measurement. Preferably, due to the significant difference between the focal lengths of the computation system and the atmospheric transmittance system, a refraction mirror 21 is installed within the lower sub-pupil to redirect the optical path, ensuring simultaneous reception of the echo signal and facilitating the integration of the receiving telescope.

[0058] Exemplarily, the receiving unit 2 includes an optical receiving unit and a subsequent spectroscopic unit. The optical receiving unit consists of a receiving telescope 20 and a folding mirror 21, while the subsequent spectroscopic unit includes a second filter 22, a beam splitter 23, a pinhole stop 24, a first filter 25, and a converging lens 26. The optical axis of the optical receiving unit is along the vertical direction, while the optical axis of the subsequent spectroscopic unit is along the horizontal and vertical directions via the beam splitter 23.

[0059] The 1064nm Mie scattered signal travels along the optical path through the receiving telescope 20, the pinhole aperture 24, the first filter 25 and the converging lens 26. The focus of the converging lens 26 coincides with the focus of the receiving telescope 20. The atmospheric backscattered light received by the receiving telescope 20 is converged into parallel light and then introduced into the first APD detector 311; the 532nm Mie scattered signal is introduced into the second ICCD detector 321 via the filter; the 1550nm Mie scattered signal is introduced into the fiber coupler 332 via the circulator 331 and then sent to the balanced detector 333.

[0060] Data processing unit 3

[0061] The data processing unit includes an atmospheric transmittance detection channel 31 , an atmospheric coherence length detection channel 32 , and an atmospheric wind field detection channel 33 .

[0062] The atmospheric transmittance detection channel 31 includes a first APD detector 311 and a first data collector 312. The first APD detector 311 is used to convert the backscattered spatial light signal generated by the interaction of the first fundamental frequency laser with atmospheric molecules and aerosol particles into an electrical signal. The first data collector 312 is used to collect the electrical signal.

[0063] The atmospheric coherence length detection channel 32 includes a beam splitter 23, a second filter 22 and a second ICCD detector 321. The beam splitter 23 and the second filter 22 are used to send the received echo signal to the target surface of the second ICCD detector 321, and the second ICCD detector 321 is used to convert the echo signal into a digital signal.

[0064] The atmospheric wind field detection channel 33 includes a circulator 331, a fiber optic coupler 332, a balanced detector 333, and a second data collector 334. The circulator 331 is used to output the echo signal to the fiber optic coupler 332, and the fiber optic coupler 332 is used to split the echo signal after beating with another local oscillator light. The balanced detector 333 is used to convert the optical signal into an electrical signal, and the second data collector 334 is used to convert the electrical signal into a digital signal.

[0065] For example, the echo signal generated by the interaction of the 1064nm wavelength laser with the atmospheric molecules enters the atmospheric transmittance detection channel 31, and after photoelectric conversion by the first ICCD detector 311, the Mie scattering echo signal of any oblique path is obtained. After the first data collector 312 receives the laser trigger signal, it continuously collects the echo signals at different heights, and outputs the atmospheric transmittance parameters after inversion calculation.

[0066] In the atmospheric coherence length detection channel 32, the second ICCD detector 321 receives the echo signal from the interaction of 532nm laser light with atmospheric molecules. The received echo signal is then transmitted to the target surface of the second ICCD detector 321 via a subsequent optical path, including the beam splitter 23 and the second filter 22. The laser's Q-switch outputs a trigger signal, triggering the second ICCD detector 321. The signal is then converted into a digital signal, forming a light spot image, which is then transmitted to the computer 4 to achieve atmospheric coherence length measurement.

[0067] The 1550nm wavelength pulsed laser interacts with the atmosphere to generate a backscattered spatial optical signal carrying wind field information. This signal is then introduced into an optical fiber and fed into the atmospheric wind field detection channel 33. The optical signal is then output to the fiber coupler 332 via a circulator 331. This signal beats the local oscillator light emitted by the Nd:YAG laser, driven by an external trigger signal card pulse signal. The signal is then split 50 / 50. The split optical signal is converted into an electrical signal by a balanced detector 333. The electrical signal undergoes A / D conversion by the second data collector 334 and outputs a digital signal. The signal power spectrum is then obtained through an FFT transformation. Finally, the pulses are accumulated to obtain a discrete power spectrum peak frequency within the range of 80±50MHz. After subtracting the AOM intermediate frequency signal of 80MHz, the output wind speed is calculated using an inversion formula.

[0068] Furthermore, the detection system also includes a computing unit 4 and a scanning platform 5 .

[0069] The calculation unit 4 is used to calculate the data of the three channels to obtain corresponding results. When receiving and processing the data output from the atmospheric transmittance detection channel 31, the calculation unit 4 obtains the data collector 312 and calculates the atmospheric transmittance; when receiving and processing the digital signal transmitted by the atmospheric coherence length detection channel 32, the calculation unit 4 can realize the atmospheric coherence length measurement. When receiving and processing the digital signal of the atmospheric wind field detection channel 33, the digital signal is transformed by FFT to obtain the signal power spectrum, and then the output wind speed is calculated by inversion using the formula.

[0070] The scanning platform 5 includes a main control board and a driver; the driver is used to control the scanning parameters of the transmitting unit and the receiving unit 2 according to the instructions of the main control board, wherein the scanning parameters include azimuth, pitch angle, speed and step length. Specifically, the scanning platform is mainly composed of a main control board and a motor driver. Stable control of the main equipment positioning and scanning detection process can be achieved. Among them, the scanning detection methods include three types: VAD scanning, PPI scanning, and RHI scanning. A photoelectric (absolute) encoder is used to control scanning parameters such as azimuth, pitch angle, speed and step length to realize the positioning, presetting, scanning, cruising and other functions of the turntable. All-round 0°-360° scanning, pitch 0°-90° scanning, the positioning accuracy can reach ±0.03°, while ensuring accuracy and meeting different atmospheric detection scanning methods on the specified path.

[0071] Furthermore, the detection system also includes a control unit, which is used to simultaneously trigger multiple lasers to generate laser pulses, and synchronously trigger the atmospheric transmittance detection channel 31, the atmospheric coherence length detection channel 32 and the atmospheric wind field detection channel 33 to perform synchronous common path data acquisition, storage and inversion.

[0072] Specifically, the control unit implements comprehensive control of the entire system, data acquisition, and information processing: First, it simultaneously triggers two lasers to generate laser pulses and synchronously triggers three receiving detection channels for simultaneous, common-path data acquisition, storage, and inversion, providing real-time display of atmospheric transmittance, atmospheric coherence length, and atmospheric wind field. Second, it provides stable and reliable control of the scanning detection process.

[0073] This implementation improves efficiency by designing two laser emission optical paths and an integrated receiving telescope to simultaneously couple the receiving optical fiber with the space light. It uses multi-sensor fusion technology, namely APD to detect atmospheric transmittance, ICCD to detect atmospheric coherence length, and balanced detector to detect atmospheric wind field. The system hardware is modularly designed, with a compact overall structure and small size. It can be moved in pitch and azimuth without changing the internal optical structure. The scanning platform can achieve stable and reliable scanning along any path. The system has a simple overall structure, a high degree of operational automation, and good long-term stability, enabling simultaneous, stable, and all-day detection of multiple parameters.

[0074] Furthermore, as shown in Figure 2, the receiving telescope utilizes an off-axis system with an integrated box-type structure; another portion houses the data processing unit. This system is compact and small, allowing for overall movement in elevation and azimuth without altering the internal optical structure. The box-type packaging prevents interference from laser emission and sky background light with the received signal, while also effectively preventing dust from contaminating the internal optical components. The optical receiving telescope utilizes a Cassegrain reflector structure. Coherent wind measurement utilizes an off-axis, co-located transmitter and receiver configuration.

[0075] In another embodiment of the present invention, a method for synchronous detection of atmospheric data on the same path is disclosed, the detection method comprising the following steps:

[0076] Use multiple lasers to synchronously emit lasers of different wavelengths on the same path;

[0077] Using a receiving telescope to receive echo signals after the interaction of lasers of different wavelengths with the atmosphere, wherein the receiving telescope is symmetrically provided with a plurality of sub-pupils;

[0078] The atmospheric data parameters are calculated respectively through the received echo signals.

[0079] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An atmospheric data same-path synchronous detection system, characterized in that: The detection system includes a transmitting unit, a receiving unit and a data processing unit; The transmitting unit includes a plurality of lasers for synchronously transmitting lasers of different wavelengths in a common path; The receiving unit comprises a receiving telescope, wherein the receiving telescope is symmetrically provided with a plurality of sub-pupils for receiving echo signals after the lasers of different wavelengths interact with the atmosphere; The data processing unit is used to calculate the atmospheric data parameters through the echo signal; The laser comprises a first laser and a second laser; The first laser is fixed above the receiving telescope and is used to simultaneously transmit a first fundamental frequency laser and a corresponding double frequency laser of a first set wavelength in the same path, and a total reflection mirror and a beam expander are sequentially installed at the front end of the first laser; The second laser is installed as a whole below the receiving telescope and is used to collimate and emit a laser of a second fundamental frequency with a second set wavelength synchronously with the first laser; The data processing unit includes an atmospheric transmittance detection channel, an atmospheric coherence length detection channel and an atmospheric wind field detection channel; The atmospheric transmittance detection channel includes a first APD detector and a first data collector, wherein the first APD detector is used to convert the backscattered spatial light signal generated by the interaction between the first fundamental frequency laser and the atmospheric molecules and aerosol particles into an electrical signal, and the first data collector is used to collect the electrical signal; The atmospheric coherence length detection channel comprises a reflector, a second filter and a second ICCD detector, wherein the reflector and the second filter are used to send the received echo signal to the target surface of the second ICCD detector, and the second ICCD detector is used to convert the echo signal into a digital signal; The atmospheric wind field detection channel includes a circulator, a fiber optic coupler, a balanced detector and a second data collector. The circulator is used to output the echo signal to the fiber optic coupler, the fiber optic coupler is used to split the echo signal after beating the echo signal with another local oscillator light, the balanced detector is used to convert the optical signal into an electrical signal, and the second data collector is used to convert the electrical signal into a digital signal.

2. The atmospheric data same-path synchronous detection system according to claim 1, characterized in that: The emission optical path of the second laser adopts off-axis emission and is co-located with the receiving optical path; The outgoing laser is kept parallel to the optical axis of the receiving telescope.

3. The atmospheric data same-path synchronous detection system according to claim 1, characterized in that: The outgoing laser of the first fundamental frequency is emitted by beam expansion and collimation; The corresponding output laser of the doubled frequency laser is emitted by beam expansion and focusing.

4. The atmospheric data same-path synchronous detection system according to claim 1, characterized in that: The receiving unit is a Cassegrain reflective structure as a whole, and an upper sub-pupil, a lower sub-pupil, a left sub-pupil and a right sub-pupil are symmetrically arranged up and down and left and right, and the distance between the two sub-pupils is greater than twice the diameter of the sub-pupil.

5. The atmospheric data same-path synchronous detection system according to claim 4, characterized in that: On the planes of the four sub-pupils, a left exit hole and a right exit hole are correspondingly arranged on the left and right sides. The left exit hole emits an exit laser of a first fundamental frequency, and the right exit hole emits a corresponding doubled frequency laser. The right exit hole is arranged on a midpoint line perpendicular to the line connecting the left and right sub-pupils.

6. The atmospheric data same-path synchronous detection system according to claim 1, characterized in that: The detection system also includes a computing unit; When the calculation unit receives and processes the data output from the atmospheric transmittance detection channel, the calculation unit obtains the data collector and calculates the atmospheric transmittance; when receiving and processing the digital signal transmitted by the atmospheric coherence length detection channel, the calculation unit is used to realize the atmospheric coherence length measurement; when receiving and processing the digital signal of the atmospheric wind field detection channel, the digital signal is transformed by FFT to obtain the signal power spectrum, and then the output wind speed is calculated by inversion formula.

7. The atmospheric data same-path synchronous detection system according to claim 1, characterized in that: The detection system also includes a scanning platform and a control unit; The scanning platform includes a main control board and a driver; the driver is used to control the scanning parameters of the transmitting unit and the receiving unit according to the instructions of the main control board, wherein the scanning parameters include azimuth, pitch angle, speed and step length; The control unit is used to simultaneously trigger multiple lasers to generate laser pulses, and synchronously trigger the atmospheric transmittance detection channel, the atmospheric coherence length detection channel and the atmospheric wind field detection channel to perform synchronous common path data acquisition, storage and inversion.

8. A method for synchronous detection of atmospheric data on the same path, characterized in that: The detection method comprises the following steps: Use multiple lasers to synchronously emit lasers of different wavelengths on the same path; The laser comprises a first laser and a second laser; Using a receiving telescope to receive echo signals after the lasers of different wavelengths interact with the atmosphere, wherein the receiving telescope is symmetrically provided with a plurality of sub-pupils; The first laser is fixed above the receiving telescope and is used to simultaneously transmit a first fundamental frequency laser and a corresponding double frequency laser of a first set wavelength in the same path, and a total reflection mirror and a beam expander are sequentially installed at the front end of the first laser; The second laser is installed as a whole below the receiving telescope and is used to collimate and emit a laser of a second fundamental frequency with a second set wavelength synchronously with the first laser; The data processing unit includes an atmospheric transmittance detection channel, an atmospheric coherence length detection channel and an atmospheric wind field detection channel; the atmospheric data parameters are calculated respectively through the received echo signals; The atmospheric transmittance detection channel includes a first APD detector and a first data collector, wherein the first APD detector is used to convert the backscattered spatial light signal generated by the interaction between the first fundamental frequency laser and the atmospheric molecules and aerosol particles into an electrical signal, and the first data collector is used to collect the electrical signal; The atmospheric coherence length detection channel comprises a reflector, a second filter and a second ICCD detector, wherein the reflector and the second filter are used to send the received echo signal to the target surface of the second ICCD detector, and the second ICCD detector is used to convert the echo signal into a digital signal; The atmospheric wind field detection channel includes a circulator, a fiber optic coupler, a balanced detector and a second data collector. The circulator is used to output the echo signal to the fiber optic coupler, the fiber optic coupler is used to split the echo signal after beating the echo signal with another local oscillator light, the balanced detector is used to convert the optical signal into an electrical signal, and the second data collector is used to convert the electrical signal into a digital signal.

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