CN-116430411-B - Atmospheric temperature and pressure synchronous measurement method based on Rayleigh Brillouin scattering spectrum

CN116430411BCN 116430411 BCN116430411 BCN 116430411BCN-116430411-B

Abstract

The invention discloses an atmospheric temperature and pressure synchronous measurement method based on Rayleigh Brillouin scattering spectrum, which belongs to the field of laser radars and comprises the steps of emitting laser in an atmospheric environment to be measured, collecting scattering echo signals of the laser, fitting the Rayleigh Brillouin scattering spectrum of the scattering echo signals in the atmospheric environment to be measured, extracting the integral linewidth f of the Rayleigh Brillouin scattering spectrum, calculating the number N s of molecular scattering photons, and substituting N s and f into an inversion model And obtaining synchronous measurement results of the atmospheric temperature T and the pressure p, wherein G 1 is a relational expression between the atmospheric temperature and the whole line width gamma and the molecular scattered photon number N s , and G 2 is a relational expression between the pressure and the whole line width gamma and the molecular scattered photon number N s . According to the invention, the relation between the characteristic parameters of the Rayleigh Brillouin scattering spectrum and the atmospheric temperature and pressure is fully excavated, a new inversion model is established, and the accurate and synchronous measurement of the atmospheric temperature and pressure can be realized.

Inventors

LIANG KUN
XU YANGRUI
WANG YUANQING
GUO YUANXIN
LI PEIZE

Assignees

华中科技大学

Dates

Publication Date: 20260505
Application Date: 20230412

Claims (6)

1. An atmospheric temperature and pressure synchronous measurement method based on a Rayleigh Brillouin scattering spectrum is characterized by comprising the following steps: Transmitting laser in an atmosphere environment to be measured, collecting scattered echo signals of the laser, and fitting a Rayleigh Brillouin scattering spectrum of the scattered echo signals in the atmosphere environment to be measured; extracting a line width corresponding to half of the peak intensity of the Rayleigh Brillouin scattering spectrum to obtain the integral line width f of the Rayleigh Brillouin scattering spectrum, and calculating the number N s of molecular scattering photons; substituting the number of molecular scattered photons N s and the integral linewidth f into a pre-established inversion model Obtaining a synchronous measurement result of the atmospheric temperature T and the pressure p; Wherein, G 1 is a pre-established relational expression between the atmospheric temperature and the whole line width gamma and the molecular scattered photon number N s , and G 2 is a pre-established relational expression between the pressure and the whole line width gamma and the molecular scattered photon number N s ; the inversion model is established as follows: setting the atmospheric temperature and the pressure as independent variables, simulating and generating a complete atmospheric scattering spectrum through a Tenti-S6 model, extracting a line width corresponding to half of the peak intensity of the scattering spectrum, and obtaining simulation results of the whole line width under different atmospheric temperatures and pressures; And setting the whole line width and the number of the molecular scattered photons as independent variables, setting the atmospheric temperature and the pressure as dependent variables, and fitting according to simulation results of the whole line width and the number of the molecular scattered photons to obtain a relational expression G 1 between the atmospheric temperature and the whole line width f and the number of the molecular scattered photons N s and a relational expression G 2 between the pressure and the whole line width f and the number of the molecular scattered photons N s , thereby obtaining the inversion model.
2. The method for synchronously measuring the atmospheric temperature and the pressure based on the Rayleigh Brillouin scattering spectrum according to claim 1, wherein the fitting mode adopted when the relational expressions G 1 and G 2 are fitted according to the simulation results of the whole line width and the molecular scattering photon number is least squares fitting.
3. The method for synchronously measuring the atmospheric temperature and the pressure based on the Rayleigh Brillouin scattering spectrum according to claim 2, wherein the inversion model is specifically as follows: Wherein, the 、、、、、、、、、 For fitting the resulting parameters, k=1, 2.
4. The method for synchronously measuring the atmospheric temperature and the pressure based on the Rayleigh Brillouin scattering spectrum according to claim 3, wherein in the inversion model, each parameter obtained by fitting is as follows: a 1 =-761.712669777197;a 2 =-29.6978370798097; b 1 =615.10733670045;b 2 =29.7650592693923; c 1 =59.3041141113125;c 2 =0.849265583010709; d 1 =-138.292171100683;d 2 =-10.1087701783764; e 1 =-2.63320622001197E-05;e 2 =-3.87820314348379E-07; f 1 =-32.7028454471183;f 2 =-0.468174377885251; g 1 =13.3050674247632;g 2 =1.16703753487656; h 1 =-5.63148756969859E-13;h 2 =-9.42749533630834E-15; i 1 =7.26564198984672E-06;i 2 =1.07026280321797E-07; j 1 =4.50847321326514;j 2 =6.45229826899901E-02。
5. The method for synchronously measuring the atmospheric temperature and the pressure based on the Rayleigh Brillouin scattering spectrum according to any one of claims 1 to 4, wherein the scattered echo signals of the laser are collected, and the Rayleigh Brillouin scattering spectrum of the scattered echo signals in the atmospheric environment to be measured is fitted through a Rayleigh Brillouin scattering spectrum mathematical model.
6. An atmospheric temperature and pressure synchronous measurement system based on rayleigh brillouin scattering spectrum, comprising: The Brillouin laser radar is used for emitting laser; the detector is used for collecting scattered echo signals of the laser; The control measurement module is used for controlling the Brillouin laser radar to emit laser in the atmosphere environment to be measured, controlling the detector to acquire a scattering echo signal of the laser, and fitting a Rayleigh Brillouin scattering spectrum of the scattering echo signal in the atmosphere environment to be measured; The calculation module is used for extracting a line width corresponding to half of the peak intensity of the Rayleigh Brillouin scattering spectrum, obtaining the whole line width gamma of the Rayleigh Brillouin scattering spectrum, and calculating the number N s of molecular scattering photons; an inversion module for substituting the number of molecular scattered photons N s and the overall linewidth f into a pre-established inversion model Obtaining a synchronous measurement result of the atmospheric temperature T and the pressure p; Wherein G 1 is a pre-established relational expression between the atmospheric temperature and the whole line width gamma and the molecular scattered photon number N s , G 2 is a pre-established relational expression between the pressure and the whole line width gamma and the molecular scattered photon number N s , and the inversion model is established as follows: setting the atmospheric temperature and the pressure as independent variables, simulating and generating a complete atmospheric scattering spectrum through a Tenti-S6 model, extracting a line width corresponding to half of the peak intensity of the scattering spectrum, and obtaining simulation results of the whole line width under different atmospheric temperatures and pressures; And setting the whole line width and the number of the molecular scattered photons as independent variables, setting the atmospheric temperature and the pressure as dependent variables, and fitting according to simulation results of the whole line width and the number of the molecular scattered photons to obtain a relational expression G 1 between the atmospheric temperature and the whole line width f and the number of the molecular scattered photons N s and a relational expression G 2 between the pressure and the whole line width f and the number of the molecular scattered photons N s , thereby obtaining the inversion model.

Description

Atmospheric temperature and pressure synchronous measurement method based on Rayleigh Brillouin scattering spectrum Technical Field The invention belongs to the field of laser radars, and particularly relates to an atmospheric temperature and pressure synchronous measurement method based on a Rayleigh Brillouin scattering spectrum. Background In the prior art, in order to measure atmospheric environment parameters, a brillouin laser radar system is utilized to emit laser signals, and the rayleigh brillouin scattering signals of laser are collected, and parameters such as temperature and pressure in the atmospheric environment are obtained by extracting characteristic parameters of brillouin scattering peaks in a scattering spectrum, so that temperature and pressure changes at different altitudes are obtained in real time. Under the prior art means, the Rayleigh scattering peak in the collected scattering spectrum and the positive and negative Stokes Brillouin peaks symmetrical to the Rayleigh scattering peak are mixed together to form a large envelope, and cannot be completely distinguished. The prior art is unstable in decomposition of internal components, synchronous measurement of atmospheric temperature and pressure cannot be realized, and meanwhile, the internal components are easily subjected to multi-value solution and the like due to larger influence of noise, so that the measurement accuracy of the atmospheric temperature or the pressure is poor finally. In order to avoid introducing internal components during measurement, in the patent document with the application publication number of CN107015243A, a temperature inversion model is directly established according to the relation between the whole line width of a scattering spectrum and the atmospheric temperature and pressure, and the model can realize temperature inversion more simply, conveniently and rapidly, and the defect is that the inversion model is a single-parameter inversion model, and accurate pressure values are needed to be known when the temperature is required to be accurately inverted. In order to avoid introducing internal components, in a system of michigan university OADS, the rayleigh brillouin scattering spectrum is simply regarded as a gaussian function, the whole linewidth of the scattering spectrum is approximately in direct proportion to the square root of the atmospheric temperature, the inversion of the atmospheric temperature is firstly realized by utilizing the relation, then the integral of the scattering spectrum on the frequency domain, namely the area surrounded by the whole profile of the scattering spectrum, is the energy of a scattering echo signal, and the relation between the energy of the scattering echo signal and the atmospheric density can be known according to a laser radar equation, so that the inversion of the atmospheric density can be realized again by utilizing the relation, and finally the inversion of the pressure is realized by utilizing the atmospheric temperature and the density. The inversion method avoids complex internal component decomposition, and can simply and rapidly acquire two spectral characteristic parameter values, thereby realizing the inversion of atmospheric temperature and pressure. However, the method ignores the influence of pressure on the whole line width, and the temperature and the pressure are jointly acted on the Rayleigh Brillouin scattering line according to the line broadening theory, so that the method has larger error on the inversion result. In addition, in applications such as weather prediction, the synchronous measurement of the atmospheric temperature and the pressure is realized, the cost can be saved, and the efficiency can be improved, so that the synchronous measurement of the atmospheric temperature and the pressure is realized, and has important practical significance, and the synchronous measurement of the atmospheric temperature and the pressure cannot be realized by the method. In order to realize multi-parameter inversion of atmospheric temperature, pressure and the like, the inversion of a plurality of atmospheric parameters can be realized theoretically only by finding a plurality of spectral characteristic parameters. Researchers have proposed that the relationship between the whole linewidth of the scattering spectrum and the atmospheric temperature and pressure is established by utilizing the linewidth of the internal Rayleigh component, thereby realizing the multi-parameter inversion of the atmospheric temperature and pressure. The method is only suitable for laboratory data with less interference by uncertain factors such as noise and the like and smoother spectral lines, and the measurement mode still depends on the internal component decomposition result of the Rayleigh Brillouin scattering spectrum, so that scattering data in an actual atmospheric environment is greatly interfered, and when the internal component decomposition is carried ou