Synchronous Measurement Method of Atmospheric Temperature and Pressure Based on Rayleigh-Brillouin Scattering Spectroscopy

Abstract

This invention discloses a method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy, belonging to the field of lidar. The method includes: emitting a laser in the atmospheric environment to be measured and acquiring the scattered echo signal of the laser; fitting the Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be measured; extracting the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum; and calculating the number of molecular scattered photons N. s ; will N s Substituting G1 and Γ into the inversion model yields the synchronous measurement results of atmospheric temperature T and pressure p; where G1 represents the atmospheric temperature and the overall linewidth Γ and the number of molecular scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed as follows: s The relationship between Rayleigh and Brillouin scattering spectra and atmospheric temperature and pressure is fully explored in this invention, establishing a new inversion model that enables accurate and synchronous measurement of atmospheric temperature and pressure.

Description

Technical Field

[0001] This invention belongs to the field of lidar, and more specifically, relates to a method for synchronous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy. Background Technology

[0002] In existing technologies, in order to measure atmospheric environmental parameters, a Brillouin lidar system is used to emit laser signals and collect Rayleigh and Brillouin scattering signals of the laser. By extracting the characteristic parameters of the Brillouin scattering peaks in the scattering spectrum, parameters such as temperature and pressure in the atmospheric environment are obtained, thereby acquiring real-time temperature and pressure changes at different altitudes.

[0003] With existing techniques, the Rayleigh scattering peak and its symmetrical forward and reverse Stokes-Brillouin peaks overlap in the collected scattering spectrum, forming a large envelope that cannot be completely distinguished. Current techniques are unstable in their internal component decomposition, making simultaneous measurement of atmospheric temperature and pressure impossible. Furthermore, the internal components are highly susceptible to noise, leading to multiple solutions; ultimately resulting in poor accuracy in atmospheric temperature or pressure measurements.

[0004] To avoid introducing internal components during measurement, the patent application with publication number CN107015243A directly establishes a temperature inversion model based on the relationship between the overall linewidth of the scattering spectrum and atmospheric temperature and pressure. This model can achieve temperature inversion more easily and quickly. The drawback is that this inversion model is a single-parameter inversion model, and accurate pressure values ​​are required to accurately invert the temperature.

[0005] Similarly, to avoid introducing internal components, the Rayleigh-Brillouin scattering spectrum in the University of Michigan's OADS system is simply treated as a Gaussian function. The overall linewidth of the scattering spectrum is approximately proportional to the square root of the atmospheric temperature. Using this relationship, the atmospheric temperature is first inverted. Then, the area enclosed by the overall profile of the scattering spectrum, which is the integral of the scattering spectrum in the frequency domain, represents the energy of the scattered echo signal. According to the lidar equation, there is a relationship between the energy of the scattered echo signal and atmospheric density. Therefore, this relationship can be used to invert the atmospheric density. Finally, the atmospheric temperature and density are used to invert the pressure. This inversion method avoids complex internal component decomposition and can quickly and easily obtain the values ​​of two spectral characteristic parameters, thus achieving the inversion of atmospheric temperature and pressure. However, this method ignores the influence of pressure on the overall linewidth. From the theory of spectral line broadening, it is known that temperature and pressure jointly affect the Rayleigh-Brillouin scattering spectrum. Therefore, this method has a relatively large error in the inversion results.

[0006] Furthermore, in applications such as meteorological forecasting, achieving simultaneous measurement of atmospheric temperature and pressure can save costs and improve efficiency. Therefore, achieving simultaneous measurement of atmospheric temperature and pressure has important practical significance, but none of the methods mentioned above can achieve simultaneous measurement of atmospheric temperature and pressure.

[0007] To achieve multi-parameter inversion of atmospheric temperature and pressure, theoretically, finding multiple spectral characteristic parameters would enable the inversion of multiple atmospheric parameters. Some researchers have proposed establishing relationships between atmospheric temperature and pressure using the overall linewidth of the scattering spectrum and the linewidth of the internal Rayleigh component, thus achieving multi-parameter inversion of atmospheric temperature and pressure. However, this method is only suitable for laboratory data with relatively flat spectral lines and minimal interference from noise and other uncertainties. Furthermore, this measurement method still relies on the internal component decomposition results of the Rayleigh-Brillouin scattering spectrum. Scattering data in actual atmospheric environments are subject to significant interference. During the internal component decomposition of the Rayleigh-Brillouin scattering spectrum, insufficient constraints lead to multi-valued solutions for the spectral characteristic parameters of the internal components. In such cases, accurate spectral characteristic parameter values ​​cannot be obtained, thus hindering precise inversion of atmospheric temperature and pressure. Therefore, this method is currently not applicable to practical atmospheric sounding applications.

[0008] Overall, in atmospheric temperature and pressure inversion methods based on scattering spectra, methods that start from the perspective of internal component decomposition suffer from instability in internal component decomposition, making them currently unsuitable for practical atmospheric temperature and pressure detection; methods that start from the perspective of external overall profiles suffer from inaccurate relationships between spectral characteristic parameters and atmospheric parameters, resulting in large errors in the inversion results. Summary of the Invention

[0009] To address the shortcomings and improvement needs of existing technologies, this invention provides a method for synchronous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy. The aim is to fully explore the relationship between the characteristic parameters of Rayleigh-Brillouin scattering spectroscopy and atmospheric temperature and pressure, establish a new inversion model, and achieve accurate and synchronous measurement of atmospheric temperature and pressure.

[0010] To achieve the above objectives, according to one aspect of the present invention, a method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy is provided, comprising:

[0011] A laser is emitted in the atmospheric environment to be tested, and the scattered echo signal of the laser is collected. The Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be tested is then fitted.

[0012] The linewidth corresponding to half the peak intensity of the Rayleigh-Brillouin scattering spectrum is extracted to obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and the number of molecular scattered photons N is calculated. s ;

[0013] The number of molecularly scattered photons N s Substituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of atmospheric temperature T and pressure p were obtained;

[0014] Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s Relational expressions between them.

[0015] Furthermore, the inversion model is established as follows:

[0016] Atmospheric temperature and pressure were set as independent variables, and the complete atmospheric scattering spectrum was generated by simulating it using the Tenti-S6 model. The linewidth corresponding to half of the peak intensity of the scattering spectrum was extracted to obtain the simulation results of the overall linewidth under different atmospheric temperatures and pressures. The simulation results of the number of molecular scattering photons under different atmospheric temperatures and pressures were obtained by using the atmospheric scattering lidar equation.

[0017] With overall linewidth and molecular scattered photon number set as independent variables, and atmospheric temperature and pressure set as dependent variables, the relationship between atmospheric temperature and overall linewidth Γ and molecular scattered photon number N is obtained by fitting the simulation results of overall linewidth Γ and molecular scattered photon number N. s The relationship expression G1 between pressure and overall linewidth Γ and number of molecular scattered photons N s From the relational expression G2, we obtain the inversion model.

[0018] Furthermore, when fitting the relationship expressions G1 and G2 based on the simulation results of the overall linewidth and the number of molecular scattered photons, the fitting method used is least squares fitting.

[0019] Furthermore, the inversion model is as follows:

[0020]

[0021] Among them, a k b k c k d k e k f k g k h k i k j k The parameters are obtained from the fitting; k = 1, 2.

[0022] Furthermore, the parameters obtained from the fitting in the inversion model are as follows:

[0023] a1=-761.712669777197; a2=-29.6978370798097;

[0024] b1=615.10733670045; b2=29.7650592693923;

[0025] c1=59.3041141113125; c2=0.849265583010709;

[0026] d1=-138.292171100683; d2=-10.1087701783764;

[0027] e1=-2.63320622001197E-05; e2=-3.87820314348379E-07;

[0028] f1=-32.7028454471183; f2=-0.468174377885251;

[0029] g1=13.3050674247632; g2=1.16703753487656;

[0030] h1=-5.63148756969859E-13; h2=-9.42749533630834E-15;

[0031] i1=7.26564198984672E-06; i2=1.07026280321797E-07;

[0032] j1=4.50847321326514; j2=6.45229826899901E-02.

[0033] Furthermore, the scattered echo signal of the laser is collected, and the Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment under test is fitted by the Rayleigh-Brillouin scattering spectrum mathematical model.

[0034] According to another aspect of the present invention, a system for synchronously measuring atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy is provided, comprising:

[0035] Brillouin lidar is used to emit lasers;

[0036] A detector used to collect the scattered echo signal of the laser;

[0037] The control and measurement module is used to control the laser emitting device to emit laser in the atmospheric environment under test, and to control the detector to collect the scattered echo signal of the laser, and to fit the Rayleigh and Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment under test.

[0038] The calculation module is used to extract the linewidth corresponding to half of the peak intensity of the Rayleigh-Brillouin scattering spectrum, obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and calculate the number of molecular scattered photons N. s ;

[0039] The inversion module is used to convert the number N of molecularly scattered photons. s Substituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of atmospheric temperature T and pressure p were obtained;

[0040] Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s Relational expressions between them.

[0041] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0042] (1) This invention fully explores the relationship between the characteristic parameters of Rayleigh-Brillouin scattering spectrum and atmospheric temperature and pressure, and establishes a new inversion model. In this inversion model, the overall linewidth of Rayleigh-Brillouin scattering spectrum and the total number of molecular scattered photons are used as characteristic parameters to invert atmospheric temperature and pressure, avoiding the unmixing of Rayleigh-Brillouin scattering, thereby avoiding the influence of noise during the decomposition of internal components, realizing the synchronous measurement of atmospheric temperature and pressure, and improving the measurement accuracy.

[0043] (2) The inversion model established in this invention is based on the following: the overall linewidth of the Rayleigh-Brillouin scattering peak is related to both atmospheric temperature and pressure, and the number of molecular scattered photons is also related to both atmospheric temperature and pressure. After analysis, the above relationship is consistent with the relationship between the characteristic parameters of the Rayleigh-Brillouin scattering spectrum and atmospheric temperature and pressure. It is not limited by the environment and can accurately measure temperature and pressure in high-altitude areas with low pressure or low-altitude areas with high pressure. It has a wide range of applications.

[0044] (3) When fitting the relationship expressions g1 and g2 based on the simulation results of the overall linewidth and the number of molecular scattered photons, the present invention uses least squares fitting. Experiments show that the inversion model obtained by this fitting method has high calculation accuracy. Attached Figure Description

[0045] Figure 1The scattering spectra provided in this embodiment of the invention are at different pressures under atmospheric temperature T = 280 K.

[0046] Figure 2 A flowchart illustrating the method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy provided in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0049] To address the technical problem that existing technologies cannot achieve simultaneous measurement of atmospheric temperature and pressure, or that the measurement results are inaccurate and cannot meet practical requirements, this invention provides a method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy. The overall idea is to fully explore the relationship between the characteristic parameters of the Rayleigh-Brillouin scattering spectrum and atmospheric temperature and pressure, and to establish an inversion model by finding multiple characteristic information beyond the internal components (Rayleigh scattering peaks and positive and negative Stokes-Brillouin peaks) in the entire Rayleigh-Brillouin scattering spectrum. This achieves simultaneous measurement of atmospheric temperature and pressure while avoiding the introduction of internal components, thereby improving measurement accuracy.

[0050] Before explaining the technical solution of the present invention in detail, the process of establishing the inversion model in the present invention will be briefly introduced as follows:

[0051] To achieve simultaneous inversion of atmospheric temperature and pressure, theoretically at least two spectral characteristic parameters need to be found. However, existing theories are often derived under relatively ideal experimental conditions, and some information is often overlooked during the derivation of related models. The University of Michigan's OADS system demonstrates that scattering spectral lines are related to temperature.

[0052]

[0053] Where T represents temperature, G m Γ(T) and Γ(T) represent the scattered spectral line and the overall linewidth at an atmospheric temperature of T, respectively. v represents the frequency of the incident laser, v0 represents the center frequency of the scattered spectral line, and Γ(T) represents the overall linewidth. The overall linewidth can be expressed as:

[0054]

[0055] Where c represents the speed of light, K represents the Boltzmann constant, and m represents the molecular weight of air.

[0056] Based on the above expression, theoretically, atmospheric temperature can be obtained simply by obtaining the overall linewidth. However, this invention has found that in actual use, the overall linewidth is related to both temperature and pressure. Specifically, from the perspective of the collision broadening principle, the spectral broadening of the scattering spectrum is affected by both Doppler broadening and collision broadening. Doppler broadening is mainly affected by temperature, while collision broadening is mainly affected by pressure. Therefore, the overall linewidth should also be affected by pressure. Figure 1 The image shows the scattering spectra at different pressures under atmospheric temperature T = 280 K. Figure 1 The spectral differences at p = 0.1 bar and p = 1 bar are easily identified. For high altitudes or low pressures, the effect of pressure is relatively small, and the spectrum can be well fitted by a Gaussian model. However, in low-altitude areas with higher pressure values, such as p = 1, the fitting results of the Gaussian model and the scattering spectrum show significant differences, such as... Figure 1 As shown. If the effect of pressure is still ignored, the measured temperature will not be corrected and will further affect the final pressure measurement result.

[0057] Therefore, this invention modifies the above model, treating the overall linewidth as a function of atmospheric temperature and pressure Γ = F1(T,p).

[0058] Furthermore, the total number of molecularly scattered photons received can be calculated using the atmospheric scattering lidar equation, which is expressed as follows:

[0059]

[0060] In the formula, N0 is the number of laser photons emitted, r is the receiving height, D is the area of ​​the receiving telescope, η is the detector quantum efficiency, η0 is the optical efficiency, and β a (T,p) is the aerosol backscattering coefficient, β m (T,p) represents the molecular backscattering coefficient, Δr represents the detection height resolution, and a(T,p) represents the extinction coefficient. These parameters can be obtained from system parameters and relevant literature in practical applications. The total number of molecularly scattered photons N can be calculated using the lidar equation. s .

[0061] The intensity of atmospheric scattered light increases with increasing molecular density and satisfies the ideal gas law pM = ρRT (where M is the molar mass of the gas, R is the ideal gas constant, and ρ is the molecular density). Therefore, the intensity of scattered light varies with changes in pressure or temperature. Figure 2As shown, the intensity of scattered light is the area of ​​the spectrum. The spectral areas are different at 280 K and pressures p of 0.1 bar and 1 bar. Therefore, the number of molecularly scattered photons can be expressed as a function N of temperature T and pressure p. s =F2(T,p).

[0062] Based on the above analysis, this invention selects the overall linewidth of the Brillouin-Rayleigh scattering spectrum and the number of molecular scattered photons to establish a synchronous inversion model for atmospheric temperature and pressure. This is achieved by simultaneously solving the equations Γ=F1(T,p) and N… s =F2)T,p) can be solved to obtain T(Γ,N) s ) and p(Γ,N s ),Right now:

[0063]

[0064] Solving the above equations directly is quite complex. This invention uses mathematical analysis for modeling. In the model building process, temperature and pressure are first set as independent variables. The complete atmospheric scattering spectrum is generated by simulating the Tenti-S6 model (a commonly used model for generating complete spectra in atmospheric simulation). Then, the Rayleigh-Brillouin scattering spectrum mathematical model (G3 model) is used to read the overall linewidth and obtain the simulation results of the overall linewidth.

[0065] The expression for the G3 model is as follows:

[0066]

[0067] In the formula, v is the frequency of the incident laser, A is a parameter representing the spectral intensity, and v B It is the frequency shift of Brillouin scattering, Γ R and Γ B These are the linewidths of the Rayleigh scattering peak and the Brillouin scattering peak, respectively. After fitting the Rayleigh-Brillouin scattering spectrum using the G3 mathematical model, the half-maximum linewidth, which is the linewidth corresponding to half the peak intensity, is the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum.

[0068] Substituting the detection system parameters into the atmospheric scattering lidar equation, the simulation results of the number of scattered photons are obtained. The overall linewidth and molecular scattered photon number at different altitudes are shown in Table 1. The atmospheric temperature and pressure are different at different altitudes.

[0069] Table 1 Overall linewidth and number of molecularly scattered photons at different heights

[0070]

[0071] After obtaining the simulation data, the overall linewidth (Γ) and photon number (N) are... sWith atmospheric temperature (T) and pressure (p) set as independent variables, and temperature (T) and pressure (p) set as dependent variables, an appropriate fitting method is used to fit the relationship between atmospheric temperature and the overall linewidth Γ and the number of molecular scattered photons N. s The relationship between G1 and pressure and the overall linewidth Γ and the number of molecular scattered photons N s By fitting the relationship expression G2, an inversion model for atmospheric temperature and pressure can be established. Experiments show that a relatively accurate inversion model can be established through least squares fitting. The final inversion model established through least squares fitting is as follows:

[0072]

[0073] Among them, a k b k c k d k e k f k g k h k i k j k The parameters obtained from the fitting; k = 1, 2;

[0074] The fitting parameters described above will yield different fitting results under different systems. By combining the specific system parameters and determining each fitting parameter, the specific expression of the inversion model can be determined. After obtaining the overall linewidth and molecular scattered photon number of the Rayleigh-Brillouin scattering spectrum, and substituting them into the inversion model, the simultaneous measurement of atmospheric temperature T and pressure p can be completed with high measurement accuracy.

[0075] The following is an example.

[0076] Example 1:

[0077] A method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy, such as... Figure 2 As shown, it includes:

[0078] A laser is emitted in the atmospheric environment to be tested, and the scattered echo signal of the laser is collected. The Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be tested is fitted. Optionally, in this embodiment, the Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be tested is fitted by a Rayleigh-Brillouin scattering spectrum mathematical model (i.e., the G3 model).

[0079] The linewidth corresponding to half the peak intensity of the Rayleigh-Brillouin scattering spectrum is extracted to obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and the number of molecular scattered photons N is calculated. s ;

[0080] The number of molecularly scattered photons N sSubstituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of atmospheric temperature T and pressure p were obtained;

[0081] Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s Relational expressions between the two;

[0082] In this embodiment, the expression for the inversion model is specifically as follows:

[0083]

[0084] Optionally, in this embodiment, the parameters of the lidar system used are shown in Table 2:

[0085] Table 2 LiDAR System Parameters

[0086]

[0087] Based on the parameters of the aforementioned lidar system, the parameters obtained by modeling through mathematical analysis in this embodiment are shown in Table 3:

[0088] Table 3 Parameters in the inversion model

[0089]

[0090] Substituting the fitting parameters in Table 3 into the inversion model yields the specific inversion model expression. In actual measurements, after obtaining the overall linewidth and molecular scattered photon number of the Rayleigh-Brillouin scattering spectrum, substituting them into the specific expression allows for the simultaneous measurement of atmospheric temperature and pressure.

[0091] In summary, this embodiment fully explores the relationship between the characteristic parameters of the Rayleigh-Brillouin scattering spectrum and atmospheric temperature and pressure, and establishes a new inversion model. In this model, the overall linewidth of the Rayleigh-Brillouin scattering spectrum and the total number of molecular scattered photons are used as characteristic parameters to invert atmospheric temperature and pressure, avoiding unmixing of Rayleigh-Brillouin scattering, thereby avoiding the influence of noise during the internal component decomposition process, realizing synchronous measurement of atmospheric temperature and pressure, and improving measurement accuracy. Furthermore, it can achieve accurate measurement of temperature and pressure in high-altitude areas with low pressure values ​​or in low-altitude areas with high pressure values, making it applicable to a wide range of situations.

[0092] Example 2:

[0093] A synchronous measurement system for atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy includes:

[0094] Brillouin lidar is used to emit lasers;

[0095] A detector used to collect the scattered echo signal of the laser;

[0096] The control and measurement module is used to control the laser emitting device to emit laser in the atmospheric environment under test, and to control the detector to collect the scattered echo signal of the laser, and to fit the Rayleigh and Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment under test.

[0097] The calculation module is used to extract the linewidth corresponding to half of the peak intensity of the Rayleigh-Brillouin scattering spectrum, obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and calculate the number of molecular scattered photons N. s ;

[0098] The inversion module is used to convert the number N of molecularly scattered photons. s Substituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of atmospheric temperature T and pressure p were obtained;

[0099] Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s Relational expressions between them.

[0100] In this embodiment, the specific parameters of the Brillouin lidar and detector are shown in Table 2 of the above embodiments; the specific implementation methods of the other modules can be referred to the description in Embodiment 1 above, and will not be repeated here.

[0101] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy, characterized in that, include: A laser is emitted in the atmospheric environment to be tested, and the scattered echo signal of the laser is collected. The Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be tested is then fitted. The linewidth corresponding to half the peak intensity of the Rayleigh-Brillouin scattering spectrum is extracted to obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and the number of molecular scattered photons N is calculated. s ; The number N of molecular scattered photons s Substituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of the atmospheric temperature T and pressure p are obtained; Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s Relational expressions between the two; The inversion model is established as follows: Atmospheric temperature and pressure were set as independent variables, and the complete atmospheric scattering spectrum was generated by simulating it using the Tenti-S6 model. The linewidth corresponding to half of the peak intensity of the scattering spectrum was extracted to obtain the simulation results of the overall linewidth under different atmospheric temperatures and pressures. The simulation results of the number of molecular scattering photons under different atmospheric temperatures and pressures were obtained by using the atmospheric scattering lidar equation. With overall linewidth and molecular scattered photon number set as independent variables, and atmospheric temperature and pressure set as dependent variables, the relationship between atmospheric temperature and overall linewidth Γ and molecular scattered photon number N is obtained by fitting the simulation results of overall linewidth Γ and molecular scattered photon number N. s The relationship expression G1 between pressure and overall linewidth Γ and number of molecular scattered photons N s The inversion model is obtained by using the relational expression G2.

2. The method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy as described in claim 1, characterized in that, When fitting the relationship expressions G1 and G2 based on the simulation results of the overall linewidth and the number of molecular scattered photons, the fitting method used is least squares fitting.

3. The method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy as described in claim 2, characterized in that, The inversion model is as follows: in, , , , , , , , , , The parameters are obtained from the fitting; k=1,2.

4. The method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy as described in claim 3, characterized in that, The parameters obtained from the fitting inversion model are as follows: a1=-761.712669777197; a2=-29.6978370798097; b1=615.10733670045; b2=29.7650592693923; c1=59.3041141113125; c2=0.849265583010709; d1=-138.292171100683; d2=-10.1087701783764; e1=-2.63320622001197E-05; e2=-3.87820314348379E-07; f1=-32.7028454471183; f2=-0.468174377885251; g1=13.3050674247632; g2=1.16703753487656; h1=-5.63148756969859E-13; h2=-9.42749533630834E-15; i1=7.26564198984672E-06; i2=1.07026280321797E-07; j1=4.50847321326514; j2=6.45229826899901E-02.

5. The method for simultaneous measurement of atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy as described in any one of claims 1 to 4, characterized in that, The scattered echo signal of the laser is collected, and the Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment under test is fitted by the Rayleigh-Brillouin scattering spectrum mathematical model.

6. A system for synchronously measuring atmospheric temperature and pressure based on Rayleigh-Brillouin scattering spectroscopy, characterized in that, include: Brillouin lidar is used to emit lasers; A detector is used to collect the scattered echo signal of the laser. The control and measurement module is used to control the Brillouin lidar to emit laser in the atmospheric environment to be measured, and to control the detector to collect the scattered echo signal of the laser, and to fit the Rayleigh-Brillouin scattering spectrum of the scattered echo signal in the atmospheric environment to be measured. The calculation module is used to extract the linewidth corresponding to half of the peak intensity of the Rayleigh-Brillouin scattering spectrum, obtain the overall linewidth Γ of the Rayleigh-Brillouin scattering spectrum, and calculate the number of molecular scattered photons N. s ; The inversion module is used to determine the number N of molecularly scattered photons. s Substituting the overall linewidth Г into the pre-established inversion model The synchronous measurement results of the atmospheric temperature T and pressure p are obtained; Where G1 represents the pre-established atmospheric temperature, overall linewidth Γ, and number of molecularly scattered photons N. s The relationship between pressure and overall linewidth Γ and the number of molecular scattered photons N is expressed in the pre-established expression. s The relationship expression between them; the method for establishing the inversion model is as follows: Atmospheric temperature and pressure were set as independent variables, and the complete atmospheric scattering spectrum was generated by simulating it using the Tenti-S6 model. The linewidth corresponding to half of the peak intensity of the scattering spectrum was extracted to obtain the simulation results of the overall linewidth under different atmospheric temperatures and pressures. The simulation results of the number of molecular scattering photons under different atmospheric temperatures and pressures were obtained by using the atmospheric scattering lidar equation. With overall linewidth and molecular scattered photon number set as independent variables, and atmospheric temperature and pressure set as dependent variables, the relationship between atmospheric temperature and overall linewidth Γ and molecular scattered photon number N is obtained by fitting the simulation results of overall linewidth Γ and molecular scattered photon number N. s The relationship expression G1 between pressure and overall linewidth Γ and number of molecular scattered photons N s The inversion model is obtained by using the relational expression G2.

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