21 results about "Differential absorption lidar" patented technology

The invention discloses a laser radar multi-gas identification method and system based on deep learning, and relates to the technical field of laser radars, and the method comprises the steps: employing a differential absorption laser radar to emit lasers with different wavelengths, receiving echo signals after gas absorption, extracting multi-domain features, and employing multi-target optimization in combination with feature importance evaluation to screen key features; generating a gas portrait of the potential gas according to the key features, and obtaining the type of the interested gas; constructing a graph structure according to the gas portrait and the gas feature similarity, performing representation learning on the graph structure by using a graph convolutional network, enhancing the graph convolutional network by using an interested gas category, constructing a gas category branch, and outputting a gas category; gas concentration branches are built by adopting a multi-layer sensor, final node representation output by the graph convolutional network is used as input, and each gas concentration is output by using linear regression. According to the invention, the distinguishing capability of small difference gases is improved, and high-precision identification and concentration inversion of multi-component gases are realized.

A lidar system for simultaneously measuring the column concentration of methane and the profile concentration of water vapor in the atmosphere is disclosed. The device includes a laser emission module: a 1645nm monoline seed laser, a 1645nm offline1 seed laser, a 1645nm offline2 seed laser, a 1064nm pump laser, a laser frequency-locking module, an optical parametric oscillator, a frequency doubling module, and emitting optical components; an echo receiving module: an integrating sphere module, an optical receiving telescope assembly, a beam splitter, filter assembly 1, filter assembly 2, photodetector 1, and photodetector 2; and a data acquisition and processing module. This invention utilizes the frequency doubling relationship between the absorption lines of methane and water vapor to simplify the complex structure of a dual-band, multi-wavelength laser. It employs seed-injected optical parametric oscillator technology to obtain a high-frequency stable 1645nm fundamental frequency light, which is then frequency-doubled to obtain an 822nm laser. The profile concentration of water vapor and the column concentration of methane in the atmosphere can be measured using differential absorption lidar (DIAL) and integral path differential absorption (IPDA) technologies, respectively.

The invention discloses a multi-path concentration difference-based carbon dioxide advection observation method. The method comprises the following steps of: arranging a foundation CO2 differential absorption laser radar and a three-dimensional wind measurement radar which can rotate at any angle in an observation area; rotating the laser radar, and sequentially enabling the observation angle position of the radar to correspond to the x axis, the middle of the x axis and the z axis, the z axis, the y axis, the middle of the z axis and the y axis in the three-dimensional wind speed coordinate system, so as to obtain a CO2 concentration profile average value and a wind speed profile average value at corresponding observation angles; based on the CO2 concentration profile average value and the wind speed profile average value, the total CO2 three-dimensional horizontal flux in the observation area is obtained through corresponding calculation. The method has the advantages that CO2 advection observation on a regional scale is realized for the first time, and the problems of poor spatial representativeness, difficulty in equipment synchronization, high cost and the like of a traditional method are solved.

The invention belongs to the technical field of atmosphere detection remote sensing, and discloses an atmosphere multi-element integrated multi-wavelength coherent differential absorption laser radar system. Lambda on1 wavelength laser generated by the first frequency stabilization seed laser, lambda on2 wavelength laser generated by the second frequency stabilization seed laser and lambda off wavelength laser generated by the third frequency stabilization seed laser are transmitted to the switching module for time domain modulation to obtain an output signal, and the output signal is decomposed into local oscillation light and a main signal by the first coupler. A main signal is modulated by the pulse modulator, amplified by the amplification module and then transmitted to the optical transceiver module, backward scattered light scattered by the atmosphere is transmitted to the second coupler and is subjected to coherent coupling and equalization with local oscillation light, and coherent electric signals are transmitted to the data analysis module through the balance detector to be analyzed. The water vapor concentration, the wind speed and the atmospheric temperature in the propagation path are obtained. Through the coherent detection technology, the signal-to-noise ratio of signals is remarkably improved, and high-precision atmospheric humidity and wind field detection is achieved.

The invention discloses a differential absorption laser radar correction method and device, equipment and a storage medium, and relates to the technical field of laser radars. The method comprises the following steps: acquiring echo signal intensity curves and first beam divergence diagrams of a plurality of angle intervals of a to-be-processed laser radar; the plurality of angle intervals comprise a first angle interval and a plurality of second angle intervals, and the echo signal intensity curve comprises echo signal intensity curves of emitted light beams with a plurality of wavelengths; executing the following operations on the emitted light beam of each wavelength: determining a first height corresponding to an echo signal intensity curve of a first angle interval and a second height corresponding to an echo signal intensity curve of each second angle interval; based on the first height and the angle interval corresponding to the first height, and each second height and the angle interval corresponding to each second height, generating a second beam divergence graph by using a preset generation algorithm; and performing correction processing on the laser radar based on the first beam divergence graph and the second beam divergence graph.

The application discloses a kind of carbon dioxide advection observation methods based on multi-path concentration difference, including in the observation region within the layout arbitrary angle rotation ground CO2 differential absorption lidar and three-dimensional wind radar;Rotary laser radar, in turn, the observation angle position of radar corresponds the x-axis in three-dimensional wind speed coordinate system, the middle of x-axis and z-axis, the middle of y-axis and z-axis, y-axis, to obtain the CO2 concentration profile average value and wind speed profile average value on corresponding observation angle;Based on CO2 concentration profile average value and wind speed profile average value, through corresponding calculation, the total amount of CO2 three-dimensional advection flux in observation region is obtained.The advantage is: first realize the CO2 advection observation on regional scale, solve the problems such as poor space representation, equipment synchronization difficulty, high cost and the like of traditional method.

A kind of lidar technology for atmospheric waveguide fast measurement, temperature and humidity profile, the key factor of atmospheric waveguide, can be measured simultaneously, the device includes laser emission module: 822nm online seed laser, 822nm offline seed laser, 1064nm pump laser, laser frequency locking module, optical parametric oscillator, acoustooptic modulator, frequency doubling module and emission optical assembly;Echo receiving module: optical receiving telescope and optical lens assembly, F-P filter, polarization light splitting prism, iodine molecular absorption cell, Fizeau interferometer and photodetector;Data acquisition and processing module.The present application fuses differential absorption lidar and two detection systems based on interferometer high spectral lidar, adopts seed injection optical parametric oscillator laser technology, obtains high frequency stability 822nm laser to realize atmospheric humidity profile fast measurement, remaining 532nm laser realizes atmospheric temperature profile fast measurement, finally inverts atmospheric waveguide parameter, realizes atmospheric waveguide efficient and accurate measurement.

The application provides a kind of methane emission source intensity estimation method and system, device, storage medium under the support of multi-source data, belong to the technical field of environmental monitoring, including based on unmanned vehicle observation obtains target evaluation methane emission point source background meteorological data;Based on differential absorption laser radar obtains target evaluation methane emission point source methane concentration data;According to the background meteorological data and the methane concentration data of the target evaluation methane emission point source obtained, a methane Gauss diffusion model is constructed;According to the methane Gauss diffusion model constructed, the methane emission source intensity estimation result is obtained by solving.The application cooperates the monitoring result of unmanned vehicle measurement and differential absorption laser radar measurement to model the methane emission source of target area based on the modeling result and solve, so as to more accurately estimate the methane emission source intensity, high accuracy, long-term sustainability monitoring.

The application discloses a laser radar multi-gas identification method and system based on deep learning, and relates to the technical field of laser radar, and comprises the following steps: a differential absorption laser radar emits laser beams with different wavelengths, receives echo signals after gas absorption, extracts multi-domain features, and adopts multi-objective optimization combined with feature importance evaluation to screen key features; the key features are used to generate a gas image of potential gas, and a gas category of interest is obtained; a graph structure is constructed according to the gas image and gas feature similarity, representation learning of the graph structure is performed by using a graph convolution network, the graph convolution network is enhanced by using the gas category of interest, a gas category branch is constructed, and a gas category is output; a multi-layer perception mechanism is used to construct a gas concentration branch, the final node representation output by the graph convolution network is used as input, and linear regression is used to output the concentrations of various gases. The application improves the distinguishing ability of small difference gases, and realizes high-precision identification and concentration inversion of multi-component gases.

The present disclosure provides a kind of dual-wavelength tunable all-solid-state mid-infrared laser, it relates to laser technical field, to solve the technical problems that high-performance dual-wavelength 3 μm band laser and its pump generation mid-infrared band laser are difficult to obtain in prior art.The mid-infrared laser includes: erbium-doped laser and optical parametric oscillator, the erbium-doped laser is used to provide dual-wavelength 3 μm band pulsed laser, wherein, erbium-doped laser includes: pump source, erbium-doped laser medium, gain modulation device, high reflection mirror and output mirror;Optical parametric oscillator is used under the pumping action of dual-wavelength pulsed laser in 3 μm band, and the mid-infrared laser of dual-wavelength output is obtained.The mid-infrared laser is simple in structure, easy to use, can obtain tunable dual-wavelength mid-infrared pulsed laser with high beam quality, meets the light source demand of differential absorption laser radar remote sensing toxic gas and photoelectric countermeasure.

An all-solid-state frequency agile filter (“AF2”) based on exotic phase change materials (PCM) and Fabry-Perot (FP) multilayer optical design is described herein. AF2 embodiments herein are useful for LIDAR (Light Detection and Ranging) applications, including DIAL (Differential absorption LIDAR), based on the AF2's benefits of fast tunability (GHz˜MHz), no moving parts, wide-range tunability, ultra-narrow bandwidth, all-solid-state, and polarization insensitivity. An AF2 consists of a single filter and a single detector, independent of the number of wavelengths needed to transmit for sampling the atmospheric water vapor, ozone, and trace gases absorption line at various spectral locations.

The application discloses a method for identifying flying targets based on coherent differential absorption laser radar, which comprises the following steps: alternately emitting laser pulses with different wavelengths into the atmosphere, obtaining Doppler spectrum information by coherently detecting echo signals; when the speed of the echo signal detection is different from the speed of the background aerosol, the Doppler spectrum shows a double-peak structure; according to the continuity of the speed of the background aerosol, judging the aerosol signal and other target signals in the double-peak signal; calculating the ratio of the echo signal strength of different wavelengths; according to the ratio result, distinguishing the flying target signal and the cloud signal outside the ambiguous distance. The application realizes the identification and distinction of the flying targets within the detection distance and the cloud signals outside the ambiguous distance based on the absorption depth difference of the echo signals by the specific gas, and realizes the detection of the concentration of the specific gas.

The application provides a laser radar-based methane fine concentration field inversion method and system, device and storage medium, and belongs to the technical field of atmospheric remote sensing monitoring, and comprises the following steps: acquiring data of the interference degree of a gas in an atmospheric environment on different wave number lasers and data of the sensitivity of different methane detection wavelengths to the atmospheric environment; determining a target methane detection wavelength based on the acquired data of the interference degree of the gas in the atmospheric environment on different wave number lasers and the data of the sensitivity of different methane detection wavelengths to the atmospheric environment; performing differential absorption laser radar observation according to the determined target methane detection wavelength; and performing methane concentration inversion on an observation signal by using a Chebyshev fitting inversion algorithm to obtain an inversion result. The laser radar-based methane fine concentration field inversion method and system can improve the precision of laser radar inversion of methane concentration and provide effective support for methane emission reduction.

The invention discloses a coherent-differential absorption laser radar capable of eliminating turbulence influence. Comprising a first seed laser, a first optical fiber amplifier, a first acousto-optic modulator, a second seed laser, a second optical fiber amplifier, a second acousto-optic modulator, a first optical fiber beam combiner, an optical fiber circulator, a telescope, a second optical fiber beam combiner, a heterodyne detector, a first radio frequency filter, a first power detector, a second radio frequency filter and a second power detector. A data acquisition card and a signal generator. The coherent-differential absorption laser radar capable of eliminating the turbulence influence has the advantages that a gas absorption signal and an atmospheric background scattering signal can be synchronously measured, the influence of the atmospheric turbulence differential absorption laser radar is reduced or even eliminated, and then the gas molecule concentration measurement precision is improved.

This invention provides an inversion method for measuring ozone using a double differential absorption lidar. This method, which belongs to the field of ozone measurement, includes: preprocessing lidar signals of all wavelengths; performing geometric overlap factor correction on the lidar signals of all wavelengths, and performing distance square correction on the lidar signals of all wavelengths; selecting the wavelength of the lidar least affected by ozone absorption, and calculating the aerosol boundary layer using the gradient method for the echo signal of this wavelength; calculating the coefficient C of the double differential absorption lidar below the aerosol boundary layer based on theories such as Mie scattering and the Jung index; and calculating the coefficient C of the double differential absorption lidar above the aerosol boundary layer based on Rayleigh scattering theory; and inverting the ozone concentration to obtain a final ozone content profile. This invention can improve the accuracy of ozone measurement.

The application provides a laser frequency stabilizing and self-calibrating device for differential absorption lidar, which divides an outgoing light beam of a seed laser of the lidar into two parts, one part is emitted to the atmosphere by a series of high-power pulsed laser output units, and the backscattered light of the atmosphere is collected and detected by a receiving optical unit; the other part is input into a series of weak-power continuous laser output units and enters a long-path absorption cell, and the transmitted light is detected. The two detection signals are sent to a signal processing board at the same time. The application uses the detection signal of the long-path absorption cell, adopts active frequency stabilizing technology to lock the frequency of the laser output light on the gas absorption spectrum, so that the laser frequency locking function is realized. At the same time, the concentration of the gas in the long-path absorption cell is known, and the real-time absorption cross section of the gas is measured based on the Lambert-Beer law, so that the system self-calibration is realized.

The invention discloses a wavelength optimization selection method for a three-wavelength differential absorption laser radar, and the method comprises the steps: introducing an intermediate wavelength between an online wavelength and an offline wavelength, and deducing a three-wavelength differential absorption laser radar inversion equation set; then, a gas absorption model is constructed based on a Voigt linear function, the relation between the absorption cross section of molecules and the temperature and the pressure intensity is established, and an equation set is established according to the temperature, the pressure intensity, the concentration, the laser wavelength and the radar signal power; and finally, discretizing the candidate wavelength interval, analyzing candidate wavelengths one by one by adopting a numerical iteration method, determining an optimal third wavelength by taking the minimum temperature inversion deviation as a criterion, and considering error influences such as molecular extinction and wavelength drift, so that high-precision atmospheric temperature and concentration multi-parameter inversion can be realized in a complex atmospheric environment. The system has good monitoring accuracy, high efficiency and practicability, and has important application value and wide market prospect.

This application discloses a method, apparatus, device, and storage medium for differential absorption lidar correction, relating to the field of lidar technology. The method includes: acquiring echo signal intensity curves and a first beam divergence map of multiple angular intervals of the lidar to be processed; the multiple angular intervals include a first angular interval and multiple second angular intervals, and the echo signal intensity curves include echo signal intensity curves of emitted beams of multiple wavelengths; for each wavelength of emitted beam, the following operations are performed: determining a first height corresponding to the echo signal intensity curve of the first angular interval and a second height corresponding to the echo signal intensity curve of each second angular interval; generating a second beam divergence map using a preset generation algorithm based on the first height and the angular interval corresponding to the first height, and each second height and the angular interval corresponding to each second height; and performing correction processing on the lidar based on the first beam divergence map and the second beam divergence map.

A system includes illumination and light collection optics configured to illuminate a targeted region of interest and receive backscattered light from the targeted region of interest. The system includes a differential absorption light detection and ranging (“DIAL”) sub-system with a first illuminator configured to emit light, through the illumination and light collection optics at a first wavelength corresponding to a first absorption peak of in an absorption curve of a first analyte of interest, and a second illuminator configured to emit light, through the illumination and light collection optics at a second wavelength corresponding to a first absorption trough in the absorption curve of the first analyte of interest, wherein the second wavelength is adjacent to the first wavelength. The system includes a controller configured to determine a concentration of the first analyte of interest in the targeted region of interest.

The invention discloses a path integral differential absorption laser radar signal enhancement system, which comprises an optical switch, an acoustic optical modulator, an erbium-doped optical fiber amplifier, a telescope, a temperature control filter, a single-photon detector and a signal acquisition card which are connected in sequence, the signal acquisition card is connected with the second laser through a power feedback control module or an error signal calculation processing module, and the temperature control filter is located in a temperature control box; the invention also discloses a signal enhancement method, which realizes dual-channel total gain consistency control by dynamically adjusting laser power of a non-absorption wavelength channel and compensating signal loss caused by filter transmittance difference, and locks a filter passband at an absorption wavelength peak value to maximize a main channel signal and improve the gain consistency of the main channel. The filter transmittance loss of the secondary channel is compensated through power regulation, and the performance compromise limitation caused by the fact that dual-wavelength passbands need to be considered in a traditional scheme is broken through.

The invention provides a escaping carbon emission AR imaging device, a gas leakage detection method and application, and belongs to the technical field of gas detection devices. The wearable device comprises a wearable device body which is provided with a communication device and an AR imaging device; and the tunable diode laser radar sensor is used for collecting and analyzing three-dimensional distribution and concentration information of the escape carbon emission gas in the surrounding space and transmitting the three-dimensional distribution and concentration information to the AR imaging device for display through the communication device. According to the tunable diode laser radar sensor, the tunable diode laser absorption spectrum technology is combined with differential absorption laser radar and time-dependent single photon counting, and long-distance spectrum detection and distance measurement of a low-power semiconductor diode laser are achieved. Based on the laser reflection theory and the spectral analysis method, the problem of limitation of the imaging distance range in the prior art is solved, the imaging range of the detection system is expanded, and the position and concentration of the gas are determined by utilizing the three-dimensional image of the gas and the physical environment occupied by the gas.