CN102288970A - Method, system and detection machine for detecting atmospheric waveguide environment - Google Patents

Abstract

The invention provides a method, a system and a detection machine for detecting atmospheric waveguide environment, wherein the method comprises the following steps of: emitting laser to the simulated atmospheric environment; obtaining backward scattering light signals detected by the laser and generated after the irradiation of aerosol particles with different radii in the simulated atmospheric environment; analyzing the backward scattering light signals detected by the laser to obtain the backward scattering characteristics of the aerosol particles with different radii; and obtaining the atmospheric waveguide characteristic parameters according to the backward scattering characteristics of the aerosol particles in different temperature, humidity and pressure environment and the atmospheric refractive index change condition. In the scheme of the invention, the laser is used for detecting the atmospheric waveguide environment, and the detection real-time performance is high.

Description

A kind of method, system and explorer of atmospheric sounding waveguide environment

Technical field

The present invention relates to the atmospheric environmental parameters field of detecting, be meant a kind of method, system and explorer of atmospheric sounding waveguide environmental parameter especially.

Background technology

Atmospheric duct is electromagnetic wave is returned and the tortuous airspace of propagating.The atmospheric duct environment can make electromagnetic wave realize the over the horizon transmission under less attenuation, under the marine environment, owing to have multiple gases and water vapor, make the electromagnetic wave propagation path bend, radar can detect the target that is several times as much as the normal observation distance, realize over-the-horizon detection and reception, the atmospheric duct environment also can make in the normal coverage area of microwave radar detectivity and cause potential blind area or weak signal phenomenon, also can cause the electromagnetic interference problem between change system complicated more.According to the mechanism that atmospheric duct forms, marine atmospheric duct mainly can be divided into: evaporation waveguide and unsettled atmospheric duct.

Evaporation waveguide occurs in ocean surface, it forms mechanism is originally to fall sharply suddenly after near the saturation vapour pressure the ocean surface rises to a certain height, satisfy the condition of vertical air index gradient less than-157n/km, cause electromagnetic wave to be retrained by this evaporation waveguide layer structure, the superrefraction phenomenon occurs in the propagation of vertical direction.The evaporation waveguide layer is generally between the 5m to 50m at the height of vertical direction, has on good stability, longer duration, the horizontal direction characteristics such as extended distance is far away, and is remote to shipborne radar, the influence of over the horizon target detection power is very big; The upper and lower wall of unsettled atmospheric duct is atmospheric envelope; Yet observation data famine and long-continued observation on a large scale such as are difficult to carry out at present situation on wide ocean, have seriously restricted the atmospheric duct Study on Technology.

Tradition atmospheric duct detection method obtains atmospheric parameters such as temperature, humidity, air pressure and wind direction usually by means of sounding equipment such as sounding rocket or balloons, calculate the refractive index that obtains the differing heights atmosphere, obtain the vertical section of refractive index, and then judge and to support the situation that exists of atmospheric duct for the over the horizon transmission provides data.

These traditional methods need be grown apart from multiple spot and gather atmospheric parameter, and dirigibility, real-time are relatively poor relatively, data acquisition cost height.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of method, system and explorer of atmospheric sounding waveguide environment, surveys the real-time height.

For solving the problems of the technologies described above, embodiments of the invention provide a kind of method of atmospheric sounding waveguide environment, comprising:

Emission laser is to simulating in the atmospheric environment;

Obtain described laser to after the different radii particulate in the described simulation atmospheric environment irradiation, the laser acquisition back scattering light signal of generation;

Scattered light signal after the described laser acquisition is analyzed, obtained the back scattering feature of the described different radii particulate of laser acquisition;

According to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment, obtain the atmospheric duct characteristic parameter.

Wherein, scattered light signal after the described laser acquisition is analyzed, the step that obtains the back scattering feature of the described different radii particulate of laser acquisition is specially:

By following formula $I_{\mathrm{sca}}={\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="HDA0000075572340000031.png,HDA0000075572340000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ Scattered light signal after the described laser acquisition is analyzed, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly strengthens;

Wherein, I ₀Be the incident light intensity, λ is an optical maser wavelength, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place, Be the scattered light intensity relevant with angle, wherein,

Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is: $S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

Wherein, according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment, the step that obtains the atmospheric duct characteristic parameter is specially:

In different temperatures, humidity and pressure environment, the distribution characteristics of the laser acquisition back scattering light signal that laser produces the particulate of different radii irradiation back and at the SEQUENCING VERTICAL refractive index gradient during less than-157N/KM, obtain the atmospheric duct characteristic parameter, wherein said atmospheric duct characteristic parameter comprises: probability that the horizontal-extending scope of the duration of ducting layer, the height of ducting layer, ducting layer, evaporation ripple layer occur and the meteorological hydrologic condition that produces evaporation waveguide.

Wherein, described Wavelength of Laser is 1.064 μ m, and the scope of described particulate radius is: 0.1 μ m～100 μ m, and described particulate refractive index is 1.55, the refractive index of gasoloid surrounding layer water is 1.33.

Embodiments of the invention also provide a kind of system of atmospheric sounding waveguide environment, comprising:

Explorer is used for launching laser to simulating atmospheric environment, and obtain described laser to the irradiation of the different radii particulate in the described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Processor is used for scattered light signal after the described laser acquisition is analyzed, and obtains the back scattering feature of the described different radii particulate of laser acquisition; And, obtain the atmospheric duct characteristic parameter according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment.

Wherein, described explorer comprises:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And

Emitting antenna is used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports described processor to.

Wherein, the transadmittance gain of described wideband low noise amplifier more than 1.5GHz, the input voltage noise less than

Input current noise less than

Wherein, described avalanche photodide biasing stepup transformer comprises: avalanche photodide, the digital temperature chip, D/A and microprocessor, wherein, described microprocessor is read current described avalanche photodide APD surface temperature value by described digital temperature chip, uses the temperature-slide-back curve under the APD fixed gain, obtains the target bias V of APD under the Current Temperatures _Goal, adjust the current bias voltage V of APD by D/A _ControlTo target bias V _Goal

9. system according to claim 8 is characterized in that, the response time 450ps of described avalanche photodide, and noise current is

Wherein, described light signal receiving subsystem also has the shield assembly that utilizes weak magnetic material to make.

Wherein, described weak magnetic material is the metallic aluminium of thickness 1.3mm.

Wherein, described processor is by following formula $I_{\mathrm{sca}}={\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="HDA0000075572340000031.png,HDA0000075572340000041.png"\; state="\{\{state\}\}">I</figure-callout>}}_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ Scattered light signal after the described laser acquisition is analyzed, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly strengthens; Wherein, I ₀Be the incident light intensity, λ is an optical maser wavelength, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place,

Be the scattered light intensity relevant with angle, wherein,

Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is: $S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

Embodiments of the invention also provide a kind of explorer, comprising:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And emitting antenna, be used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports the processor that is connected with described explorer to.

The beneficial effect of technique scheme of the present invention is as follows:

In the such scheme, by in the simulation atmospheric environment, launching laser, and acquisition laser acquisition backward scattered light light signal, further obtain back scattering feature to the particulate in the simulation atmospheric environment, in real time the atmospheric duct environment is surveyed, obtain the atmospheric duct characteristic parameters such as thickness, expanded range and duration of ducting layer, support for military activities such as atmospheric duct over-the-horizon detection provide the atmospheric duct environmental data.This method has improved the accuracy of atmospheric duct forecast, has solved and has utilized weather to estimate the not accurate enough problem of waveguide parameter that the refractive index method provides; This method sampling precision height, data volume are big, convenient, flexible, solved and utilized the long and horizontal range expansion of time that lags of radiosondage device measuring condition harshness, measurement result to go up problems such as representative difference, it is relatively poor to remedy over-the-horizon radar distance and bearing resolution, the dissatisfactory present situation of bearing accuracy.

Description of drawings

Fig. 1 is the method flow diagram of atmospheric sounding waveguide environment of the present invention;

Fig. 2 is the principle schematic of laser acquisition atmospheric duct;

Fig. 3 is the laser light scattering model of single particle;

Fig. 4 A, Fig. 4 B are the aerocolloidal laser light scattering simulation result of different refractivity;

Fig. 5 A, Fig. 5 B are the aerocolloidal laser light scattering simulation result of different radii;

Fig. 6 is the Laser emission and the light signal receiving system of laser detection system of the present invention;

Fig. 7 is laser detection system circuit theory diagrams of the present invention;

Fig. 8 is a broadband transconductance amplifier circuit schematic diagram;

Fig. 9 is the structured flowchart of self-adaptation numerical control bias booster system;

The microprocessor work process flow diagram of Figure 10 self-adaptation numerical control bias voltage system;

Figure 11 is laser acquisition experiment synoptic diagram;

Figure 12 A, Figure 12 B, Figure 12 C are laser acquisition experiment echoed signal figure;

Figure 13 A, Figure 13 B, Figure 13 C laser acquisition experiment echoed signal figure;

Figure 14 A, Figure 14 B, Figure 14 C and Figure 14 D laser acquisition experiment echoed signal figure.

Embodiment

For making the technical problem to be solved in the present invention, technical scheme and advantage clearer, be described in detail below in conjunction with the accompanying drawings and the specific embodiments.

The present invention is directed to traditional atmospheric duct detection method need grow apart from multiple spot collection atmospheric parameter, dirigibility, real-time are relatively poor relatively, the problem that the data acquisition cost is high provides a kind of method, system and explorer of atmospheric sounding waveguide environment, surveys the real-time height.

As shown in Figure 1, the method for atmospheric sounding waveguide environment of the present invention comprises:

Step 11, emission laser is to simulating in the atmospheric environment;

Step 12 is obtained described laser to after the different radii particulate in the described simulation atmospheric environment irradiation, the laser acquisition back scattering light signal of generation;

Step 13 is analyzed scattered light signal after the described laser acquisition, obtains the back scattering feature of the described different radii particulate of laser acquisition;

Step 14 according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment, obtains the atmospheric duct characteristic parameter.

Such scheme of the present invention is by launching laser in the simulation atmospheric environment, and acquisition laser acquisition backward scattered light light signal, further obtain back scattering feature to the particulate in the simulation atmospheric environment, in real time the atmospheric duct environment is surveyed, obtain the atmospheric duct characteristic parameters such as thickness, expanded range and duration of ducting layer, support for military activities such as atmospheric duct over-the-horizon detection provide the atmospheric duct environmental data.This method has improved the accuracy of atmospheric duct forecast, has solved and has utilized weather to estimate the not accurate enough problem of waveguide parameter that the refractive index method provides; This method sampling precision height, data volume are big, convenient, flexible, solved and utilized the long and horizontal range expansion of time that lags of radiosondage device measuring condition harshness, measurement result to go up problems such as representative difference, it is relatively poor to remedy over-the-horizon radar distance and bearing resolution, the dissatisfactory present situation of bearing accuracy.

Further, in the foregoing description, step 13 is based on that Mie theory carries out when specific implementation, be specially:

By following formula $I_{\mathrm{sca}}=I_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ Scattered light signal after the described laser acquisition is analyzed, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly is enhanced;

Wherein, I ₀Be the incident light intensity, λ is an optical maser wavelength, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place,

Be the scattered light intensity relevant with angle, wherein,

Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is: $S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

As Fig. 2, shown in Figure 6, send laser by pulse laser emission subsystem, laser pulse is propagated in atmosphere, have an effect with heterogeneity gasoloid etc., scattering phenomenon constantly takes place in laser beam in atmospheric environment, the back scattering light signal that is loaded with different radii gasoloid information is received by the light signal receiving subsystem, because laser is to the aerocolloidal scattering signatures difference of different radii, the back scattering light signal that collects is also different, judges aerocolloidal physical characteristics in the atmospheric environment according to the return laser beam feature.

The essential condition that the ocean produces atmospheric duct is the relative humidity of atmosphere, the relative humidity of marine atmosphere affects the aerocolloidal physical characteristics of evaporation waveguide atmospheric environment, the particulate of different physical features is also had nothing in common with each other to the light scattering characteristic of laser, utilizes air index and relative humidity, relative humidity and aerocolloidal relation to set up just based on the atmospheric duct detection method of laser technology.

The laser scattering properties of different physical features particulates is had nothing in common with each other again.According to Mie theory, as shown in Figure 3, radius is that the particle of R is m=m with respect to the refractive index complex representation of surrounding medium ₁+ jm ₂, the refractive index of medium is n, imaginary part is not equal to the null representation particle absorption.Getting the particle center is true origin O, and the vacuum medium wavelength is that λ, intensity are I ₀Linearly polarized light incide on the particle scattered light along the z axle

And the scattering angle between the incident light direction is θ, and the electric vector of incident light with respect to the angle of scattering surface is

If incident light is that intensity is I ₀Natural light, then at a distance of the scattered light intensity of ordering be for the P of R place with the atmosphere center O:

$I_{\mathrm{sca}}=I_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})---\left(1\right)$

The scattered light intensity relevant in the formula (1) with angle

For:

I in the formula (2) ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane respectively, and S1, S2 represent the amplitude function, and its infinite series form is:

$S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]---\left(3\right)$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]---\left(4\right)$

A in formula (3), (4) _n, b _nBe the Mie scattering coefficient, the ratio that is single particle yardstick r and light wavelength lambda is the function of parameter alpha (α=2 π r/ λ).Particulate yardstick and optical maser wavelength determine the scattering of single particle jointly as can be known, further determine the scattering properties of population.

The radius of particulate generally is not more than 10 ²μ m for maritime gasoloid, is a concentration maximum about 1-16 μ m at radius.During emulation, optical maser wavelength is got 1.064 μ m and 0.532 μ m respectively, and marine aerosol particle refractive index is got n=1.55, and the refractive index of gasoloid surrounding layer water is got n=1.33.

According to the computing formula of Mie scattering theory, make lambda1-wavelength λ=1.064 μ m, particle radii are 1 μ m, when the gasoloid refractive index was got n=1.55, n=1.33 respectively, the scattering situation of single particle was respectively shown in Fig. 4 A, Fig. 4 B.Horizontal ordinate is a scattering angle, and ordinate is the common logarithm of scattering strength, and ' uprightness ' expression incident light electric vector is vertical with the scattering plane, ' parallel ' expression incident light electric vector and scattering plane parallel.Scattered light mainly concentrates on forward direction as can be seen from Fig. 4 A, Fig. 4 B, and when scattering angle was near 180 °, scattered light intensity obviously strengthened again, i.e. back scattering obviously strengthens.

Make lambda1-wavelength λ=1.064 μ m, the gasoloid refractive index is got n=1.55, and when particle radii were respectively r=10 μ m, 50 μ m, the scattering situation of single particle was shown as Fig. 5 A, Fig. 5 B respectively.When bubble radius increases gradually, the corresponding increase of scattered intensity, the asymmetry of light distribution is strengthened gradually, and the forward scattering light intensity is more a lot of than back scattering light intensity, and particularly near the scattered light intensity scatteringangle=0 ° more becomes sharp-pointed.Yet, increase along with bubble radius, the absolute value of backscatter intensity increases gradually, particularly near the backscatter intensity scatteringangle=180 ° increases apparent in view, when bubble radius R＞10 μ m, formed a more sharp-pointed peak value near 180 ° of scattering angle, radius is big more, and peak strength is big more.

By simulation analysis as can be known, at the aerocolloidal radius distribution scope of evaporation waveguide environment (0.1～100 μ m), particulate will produce the back scattering light signal of certain intensity under the incident of laser, and increase along with particle radii, scattered intensity correspondingly is enhanced, scattering angle is that 180 ° the peak signal of rear orientation light is more outstanding, surveys advantageous conditions is provided for utilizing aerocolloidal back scattering light signal to carry out atmospheric duct.

Preferably, above-mentioned steps 14 is specially: in different temperatures, humidity and pressure environment, the distribution characteristics of the laser acquisition back scattering light signal that laser produces the particulate of different radii irradiation back and at the SEQUENCING VERTICAL refractive index gradient during less than-157N/KM, produce atmospheric duct, and can obtain the atmospheric duct characteristic parameter, wherein said atmospheric duct characteristic parameter comprises: probability that the horizontal-extending scope of the duration of ducting layer, the height of ducting layer, ducting layer, evaporation ripple layer occur and the meteorological hydrologic condition that produces evaporation waveguide.

Specifically, according to radar band air index model, analyze and to obtain the influence of different atmospheric temperatures, humidity, pressure environment air index.

The SEQUENCING VERTICAL variations in refractive index is the common decision condition of atmospheric sounding waveguide.The atmospheric environment of different humidity, temperature, pressure is determining the radiowave air index.In the atmosphere convection layer, the refraction index N of atmosphere (radio refractive index) with the pass of temperature, air pressure, vapour pressure is:

$N=\frac{A}{T}(P_a+\frac{\mathrm{Be}}{T})---\left(5\right)$

In the formula (5), P _aBe air pressure (hPa); E is vapour pressure (hPa); T is temperature (K); The constant that A, B determine for experiment.Know that by formula (1) air index index N changes along with the variation of atmospheric temperature, air pressure, vapour pressure.In vertical height is below the 50m, produces in the naval air environment of evaporation waveguide atmospheric temperature T and atmospheric pressure P _aVariation not obvious relatively, its air index vertical distribution mainly changes along with airborne relative humidity, air index index N depends primarily on the variation of vapour pressure e.After near the saturation vapour pressure the ocean surface rises to a certain height, fall sharply suddenly, satisfy the condition of vertical air index gradient, promptly produce the marine atmosphere waveguide less than-157N/km.

Specifically, set up the model of the atmospheric duct environment of different humidity, temperature, pressure to the gasoloid change in physical properties, and obtain laser acquisition by experiment and obtain this type of aerocolloidal back scattering feature, further obtain laser echo signal and atmospheric duct environmental relation.

Aerocolloidal physical characteristics mainly is subjected to the influence of relative humidity in the low latitude, ocean.When the steam of ocean evaporation condensed on particulate, very big change can take place in the physical characteristics of particulate.When relative humidity is f, the ratio of aqueous aerosol particle radii r (f) and dry gas sol particles radius r, available below experimental formula calculate:

$P=\frac{r\left(f\right)}{r}={(1-f)}^{-\frac{1}{\mathrm{\&mu;}}}---\left(6\right)$

μ is a constant coefficient in the formula.For marine atmosphere, μ=3.9.For atmosphere pollution, μ=4.4.If relative humidity f is known, just can try to achieve the ratio P of aqueous aerosol particle radii and dry gas sol particles radius by formula (6).The relative humidity of atomsphere variation directly affects aerocolloidal physical characteristics, further influences aerocolloidal laser backscattering characteristic.Because it is originally to fall sharply suddenly after near the saturation vapour pressure the ocean surface rises to a certain height that the marine atmosphere waveguide forms mechanism, must cause in the atmosphere aerocolloidal change in radius very obvious, by aerocolloidal laser back scattering changing features, can carry out inverting to the atmospheric environment changing features, judge whether atmospheric duct produces.

Further,, survey correction on the spot, finish marine atmosphere waveguide laser detection model, further obtain the atmospheric duct characteristic parameter with system by the ocean according to aerocolloidal laser back scattering feature in the different humidity of marine atmosphere, temperature, the pressure environment.

The atmospheric duct characterisitic parameter comprises: the probability that the horizontal-extending scope of the duration of ducting layer, the height of ducting layer, ducting layer, evaporation waveguide occur, the meteorological hydrologic condition that produces the sea evaporation waveguide, these parameters are relevant with aerocolloidal distribution characteristics.Utilize the method for laser acquisition to carry out real-time detection to naval air environment, by the laser echo signal feature, obtain gasoloid distribution characteristics in the marine atmosphere, in conjunction with ocean result of detection on the spot, laser acquisition atmospheric duct model is revised, for the development of atmospheric duct laser radar provides support.

In the above embodiment of the present invention, described Wavelength of Laser is preferably 1.064 μ m, and the scope of described particulate radius is: 0.1 μ m～100 μ m, and described particulate refractive index is 1.55, the refractive index of gasoloid surrounding layer water is 1.33.

As shown in Figure 6, the system for atmospheric sounding waveguide environment of the present invention comprises:

Explorer is used for launching laser to simulating atmospheric environment, and obtain described laser to the irradiation of the different radii particulate in the described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Processor is used for scattered light signal after the described laser acquisition is analyzed, and obtains the back scattering feature of the described different radii particulate of laser acquisition; And, obtain the atmospheric duct characteristic parameter according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment.

Wherein, as shown in Figure 6 and Figure 7, described explorer comprises:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And

Emitting antenna is used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports described processor to.

Wherein, the transadmittance gain of described wideband low noise amplifier more than 1.5GHz, the input voltage noise less than

Input current noise less than

Wherein, described avalanche photodide biasing stepup transformer also comprises: avalanche photodide, the digital temperature chip, D/A and microprocessor, wherein, described microprocessor is read current described avalanche photodide APD surface temperature value by described digital temperature chip, uses the temperature-slide-back curve under the APD fixed gain, obtains the target bias V of APD under the Current Temperatures _Goal, adjust the current bias voltage V of APD by D/A _ControlTo target bias V _Goal

Wherein, the response time 450ps of described avalanche photodide, noise current is

Wherein, described light signal receiving subsystem also has the shield assembly that utilizes weak magnetic material to make.

Wherein, described weak magnetic material is the metallic aluminium of thickness 1.3mm.

Describe in detail below and utilize the laser acquisition machine the different-grain diameter aerocolloidal detection experiment that distributes.

(1), laser radar model machine parameter.

As shown in Figure 6, this explorer mainly comprises pulse laser emission subsystem and light signal receiving subsystem.It is that the original beam that laser instrument sends is collimated and expands bundle and adjust that the Laser emission subsystem mainly acts on, to improve beam quality.The light signal receiving subsystem is made up of receiving optics, detector, wideband low noise amplifier, avalanche photodide biasing booster system, low ripple electric power system, and main effect is to receive the laser acquisition back scattering light signal that is loaded with gasoloid information.The model machine parameter is: semiconductor pumped YAG pulsed laser pulse energy P=20mJ, pulse width T=10ns, laser wavelength lambda=1.064 μ m, Laser emission bore 25mm receives bore 100mm, and the echo samples frequency is 800M, detection accuracy is 0.1875m, surveys range 2.2V.

(2), the laser radar explorer also has following several aspects feature:

(1) selects the shielding material of weak magnetic material metallic aluminium as the light signal receiving subsystem.This material magnetic flux density B and magnetic field intensity H are linear relationships, and μ _rIn the environment of optional frequency, remain constant, be easy to get by computation of table lookup, when interfering frequency during at 100KHz to 1GHz, if the absorption loss that requires screen layer is greater than 40dB, the thickness of required weak magnetic material metallic aluminium is at least 1.28mm.Because the general mode that adopts several high-voltage capacitors to spark of the high power laser of pulse mode work provides energy for pumping source, the instantaneous suction electric current of luminous moment laser instrument can be up to more than the 70A, and the duration is as short as nanosecond, the big electric current of this transition can produce strong electromagnetic radiation around laser instrument, laser power supply case and power lead, cause receiver and testing apparatus to be subjected to strong jamming.When explorer designed, the metallic aluminium of selecting used thickness 1.3mm was as shielding material.

(2) the low noise optimization technology of selection wide band high-gain trsanscondutance amplifier, its advantage is not have sample resistance, has low noise, high sensitivity and wide bandwidth performance, is convenient to reception and processing to light signal.Owing to a little less than the laser back scattering very of far field target, need detector that higher gain and lower noise are arranged.APD is output as the low current signal of μ A magnitude, for its electric current---and voltage transitions (I-V) mainly can be selected to use sample resistance to carry out the I-V conversion and finish I-V conversion dual mode with trsanscondutance amplifier.But because the junction capacity of APD and because the summation of the stray electrical capacity that wiring causes can constitute low-pass filter with sample resistance can not meet the demands on the bandwidth performance, and sample resistance can introduce extra noise, is unfavorable for the low noise index of system.During prototype design, select to use high-performance OP amplifier to form trsanscondutance amplifier and finish I-V convert task (as shown in Figure 8) to the avalanche photodide output signal, R1 and C1 are used for reducing the direct current that caused by the operational amplifier input bias current and exchange error.Under certain condition, for illustrated trsanscondutance amplifier, there are following relation in output voltage and input current:

V _o＝-I _s·R _F (7)

V in the formula _oOutput voltage for trsanscondutance amplifier; I _sBe input current; R _FBe feedback resistance.

(3) optimisation technique of the wide imported adjustable operational amplifier of selection high-gain broadband.About the problem of choosing of operational amplifier, consider that the bias current of operational amplifier chip should be more much smaller than the minimum signal electric current that detects, make input bias current as far as possible less than 10pA; When satisfying wider bandwidth, guarantee that amplifier has 10 ³The transadmittance gain of the order of magnitude, must select that 1.5GHz is above, the input voltage noise less than

Input current noise less than

The operational amplifier of higher gain bandwidth product, in conjunction with the needs that laser acquisition is tested, choose the imported adjustable operational amplifier chip of low noise FET under different atmospheric environments, model is OPA657.But the power supply of the external linear DC of amplifier can produce noise, these by the mutual conductance enlargement factor 10 ³The V/A order of magnitude amplifies the back output noise can be amplified to the mV order of magnitude easily.During design, the bypass circuit of selective amplifier filters noise, uses lithium battery power supply instead and shortens power lead, further reduces system noise.

(4) APD self-adaptation numerical control bias pressure build-up technique.Avalanche photodide is very responsive to temperature, and the temperature rising can make snowslide pipe multiplication factor that significantly change takes place, and influences result of detection.Adopt the APD self-adaptation temperature control booster system of high precision high stability degree can follow the tracks of and compensate because the APD gain error that temperature variation causes.The booster system structured flowchart as shown in Figure 9.With traditional discrete component is that main temperature control circuit is compared, and this circuit has that circuit is succinct, noise is low, precision is high, is subjected to extraneous and the little advantage of factor affecting is installed, and has guaranteed the performance index of system preferably.The course of work is as follows: the digital temperature chip is close to the APD installation, under the control of microprocessor, accurately reads current APD surface temperature value T.Microprocessor uses temperature---the slide-back curve under the APD fixed gain of inner burning, obtains the target bias V of APD under the Current Temperatures _Goal, processor is adjusted the current bias voltage V of APD by D/A converter _ControlTo target bias V _Goal, this adjustment process is monitored by one road A/D converter.The software workflow of microprocessor as shown in figure 10.

(3), experimentation.

In laboratory building corridor (90 meters long), simulate different humiture atmospheric environments, utilize Laser emission and receiving system, obtain laser to the aerocolloidal backscattering echo signal of different particle radii, by the echoed signal signature analysis, further specify the characteristic and advantage of the method for laser acquisition atmospheric duct.The experiment synoptic diagram as shown in figure 11.

Experiment one, ambient atmosphere temperature are that 15.6C, relative humidity are 55.6%.Utilizing common humidifier to produce radius is the particulate of 1 μ m to 10 μ m, the atmospheric environment of analog approximation cigarette, water cloud.Utilizing self-control laser radar model machine that humidifier is produced radius is that the water atomization particle of 1 μ m to 10 μ m is surveyed, and gathers 10 groups of filtered echoed signals of data mean value such as Figure 12 A, the echoed signal when not adding gasoloid in the atmosphere; Figure 12 B is that 20 meters relative humidity are 82.3% echoed signal; Figure 12 C is that 45 meters relative humidity are 85.6% echoed signal.

Experiment two, the big atmospheric temperature of environment are that 18.6 ℃, relative humidity are 52.5%.Utilize the common steam flatiron, producing radius size is the particulate of 0.1 μ m to 10 μ m, and obviously range of scatter is 0 to 3 meter, the atmospheric environment of the approximate cigarette of simulation different temperatures and humidity, dirt, mist, haze.The radius that utilizes self-control laser radar model machine that vapour iron is produced is that the particulate of 0.1 μ m to 10 μ m is surveyed.Gather 10 groups of filtered echoed signals of data mean value such as Figure 13 A and be the echoed signal when not adding gasoloid in the atmosphere; Figure 13 B for vapour iron when 25 move 35 meters, temperature is that 22.2 ℃, relative humidity are 87.5% echoed signal; Figure 13 C for vapour iron when 25 move 35 meters, temperature is that 23.1 ℃, relative humidity are 95.2% echoed signal.

Experiment three, ambient atmosphere temperature are that 21.6 ℃, relative humidity are 62.5%.Utilize common sprayer, the generation radius is 10 to 100 microns a particle, and obviously range of scatter is 0 to 1 meter, the simulation different temperatures and the approximate mist of humidity, the atmospheric environment of the spray.Utilize model machine that the particle (radius is 10 μ m to 100 μ m) that sprayer produces different temperatures is surveyed, obviously range of scatter is 0.5 to 1 meter, gather 10 groups of filtered echoed signals of data mean value such as Figure 14 A, the echoed signal when not adding gasoloid in the atmosphere; Figure 14 B, for being respectively 95.6% and 90.2% 20 and 30 meters, relative humidity respectively, and temperature is that 24.5 ℃, spread of spray are 0.5 meter echoed signal; At 30 and 65 meters, and relative humidity is 100% to Figure 14 C, temperature is that 25.0 ℃, spread of spray are 0.5 meter echoed signal for respectively; Figure 14 D is for being that 1 meter and 45 meters spread of sprays are 0.5 meter at 25 place's spread of sprays respectively, and relative humidity is 95.3%, temperature is 25.2 ℃ echoed signal.

(4), interpretation.

This experiment controllability is good, workable, can be provided with atmospheric parameter and size distribution as required, is convenient to analyze with theoretical research.Obtain by experiment, laser back scattering degree to the different radii particle under different temperature, damp condition is also had nothing in common with each other.Under the identical atmospheric conditions, the particle radii size changes from 0.1 μ m to 100 μ m, to scattered signal intensity gradually strengthen thereafter, the particle density scope is big more, signal intensity is also big more, and particle same radius size of the same race, humidity change more greatly backscatter intensity more greatly, show that the method for utilizing the laser acquisition atmospheric duct is feasible, characteristics and with the obvious advantage.

(1) detection sensitivity height.It is the laser of 1.06 μ m that wavelength is adopted in experiment, is that the particulate of 0.1 μ m to 100 μ m is surveyed to radius.By experiment one as can be known, humidifier generation radius is that the water atomization Particle Density of 1 μ m to 10 μ m is little more than producing the aerocolloidal density of evaporation waveguide, when utilizing laser that the population at 20 meters is surveyed, thereafter stronger to scattered signal, when population moves to the 45m place, can also collect tangible backscatter signal.Tested 3 o'clock, when spread of spray was increased to 1m by 0.5m, its echoed signal had also increased by force several times, and still can collect the echoed signal of particle at 65 meters.Experiment shows, because the yardstick of atmospheric aerosols such as optical maser wavelength and cigarette, dirt, steam is suitable, adds that laser pulse width can reach the detection sensitivity height of ns level, photodetector, utilizes the laser technology atmospheric duct to have very high sensitivity.

(2) spatial and temporal resolution height.Carry out in the process in experiment two, the scope that produces particle along with vapour iron changes slightly, to scattered signal peak value scope just at once change thereafter, when vapour iron when 25 meters are moved 35 meters, because airborne particulate is diffusion in time not, the peak value scope that its echoed signal keeps is broad also.Experiment shows that this method adopts innovative technologies such as the reception of High-speed transient light signal, high-speed data acquisition, the temperature control of avalanche photodide self-adaptation, and mould/number sample frequency is 800MHz, and sampling precision is 0.1875m, has higher spatial and temporal resolution.

Relation from air index variation and relative humidity, relative humidity and gasoloid physical characteristics, having set up the laser backward scattered light gets in touch with the theory that produces the evaporation waveguide condition, simulated the atmospheric environment that produces evaporation waveguide by experiment, the aerocolloidal backscattering characteristic of laser acquisition different characteristic has been done comparative analysis.Studies have shown that, angle from relative humidity of atomsphere, this new method that the research and utilization laser technology is surveyed evaporation waveguide is feasible, but have advantages such as detection sensitivity height, spatial and temporal resolution height, strong interference immunity, strong security, the good all weather operations of real-time, more can adapt to the military requirement of real-time prediction atmospheric duct environment under the complicated condition of battlefield.

Embodiments of the invention also provide a kind of explorer, comprising:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And

Emitting antenna is used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports the processor that is connected with described explorer to.

Preferably, this processor is according to following formula $I_{\mathrm{sca}}=I_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ To described

Scattered light signal is analyzed after the laser acquisition, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly strengthens; Wherein, I ₀Be incident light intensity, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place,

Be the scattered light intensity relevant with angle, wherein, Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is:

$S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

The present invention is based on the laser relative theory that aerocolloidal light scattering feature and radiowave air index change in atmospheric environments such as different temperatures, humidity, air pressure, the relational model of atmospheric physics key element when setting up laser backscattering echo signal characteristic and ducting occurring, correlation parameter according to return laser beam changing features inverting waveguide environment, judge whether to produce ducting in real time, support for military activities such as microwave atmospheric duct over-the-horizon radar over-the-horizon detection provide the atmospheric environment data.

Atmospheric duct laser acquisition method of the present invention has following technique effect:

(1) detection sensitivity height.The present invention is based on Michaelis back scattering theory, adopt about 1 micron laser, comprehensive, real-time detection.Because the yardstick of atmospheric aerosols such as optical maser wavelength and cigarette, dirt, steam is suitable, add that laser pulse width can reach the detection sensitivity height of ns level, photodetector, the information such as light intensity, frequency, phase place and polarization of the atmospheric scattering light that comprises in the laser atmosphere echoed signal, can survey multiple atmospheric physics key element, so the laser acquisition aerosol has very high detection sensitivity.

(2) spatial and temporal resolution height.The present invention adopts SAE500VS3 type low noise avalanche photodide, and (response time 450ps, noise current is about ) reception High-speed transient faint optical signal; Select high-Speed Data-Acquisition Module, mould/number sample frequency 800MHz, sampling precision are 0.1875m (3.0 * 108/800 * 106/2).The employing energy is that the laser instrument of 20mJ can be surveyed the evaporation waveguide environment of horizontal 2Km, height 0.2Km effectively.

(3) good confidentiality.Under the complex electromagnetic environment of battlefield, utilize the radar wave detection atmospheric duct to give away one's position easily, and be vulnerable to disturb and attack.Because Laser Transmission has unidirectional (it is following that the angle of divergence can be controlled in 1mrad) and good confidentiality, is not easy to be intercepted and captured with the waveguide of laser radar atmospheric sounding, has very high disguise.Without radar start, can obtain the waveguide environmental parameter afield, for the communication and the over-the-horizon detection of radar provides data refer by laser acquisition.

(4) strong anti-interference performance.The laser work frequency range that adopts is different with working frequency range such as radar, communication facilitiess, and equipment room does not exist and interferes with each other, and more is not subjected to extraneous electromagnetic interference (EMI), and is same effective under complex electromagnetic environment.

(5) universality and practical.Because laser wave length, under the said function situation, the size of light dual-mode antenna is more much smaller than microwave communication antenna, and advantages such as the laser acquisition atmospheric duct has that power consumption is little, volume is little, in light weight, low cost are easy to technological achievement transform, and are practical.

The above is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from principle of the present invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (13)

1. the method for an atmospheric sounding waveguide environment is characterized in that, comprising:

Emission laser is to simulating in the atmospheric environment;

Obtain described laser to after the different radii particulate in the described simulation atmospheric environment irradiation, the laser acquisition back scattering light signal of generation;

Scattered light signal after the described laser acquisition is analyzed, obtained the back scattering feature of the described different radii particulate of laser acquisition;

According to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment, obtain the atmospheric duct characteristic parameter.

2. method according to claim 1 is characterized in that, scattered light signal after the described laser acquisition is analyzed, and the step that obtains the back scattering feature of the described different radii particulate of laser acquisition is specially:

By following formula $I_{\mathrm{sca}}=I_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ Scattered light signal after the described laser acquisition is analyzed, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly strengthens;

Wherein, I ₀Be the incident light intensity, λ is an optical maser wavelength, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place,

Be the scattered light intensity relevant with angle, wherein,

Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is: $S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

3. method according to claim 2 is characterized in that, according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment, the step that obtains the atmospheric duct characteristic parameter is specially:

In different temperatures, humidity and pressure environment, the distribution characteristics of the laser acquisition back scattering light signal that laser produces the particulate of different radii irradiation back and at the SEQUENCING VERTICAL refractive index gradient during less than-157N/KM, obtain the atmospheric duct characteristic parameter, wherein said atmospheric duct characteristic parameter comprises: probability that the horizontal-extending scope of the duration of ducting layer, the height of ducting layer, ducting layer, evaporation ripple layer occur and the meteorological hydrologic condition that produces evaporation waveguide.

4. according to each described method of claim 1-3, it is characterized in that described Wavelength of Laser is 1.064 μ m, the scope of described particulate radius is: 0.1 μ m～100 μ m, described particulate refractive index is 1.55, and the refractive index of gasoloid surrounding layer water is 1.33.

5. the system of an atmospheric sounding waveguide environment comprises:

Explorer is used for launching laser to simulating atmospheric environment, and obtain described laser to the irradiation of the different radii particulate in the described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Processor is used for scattered light signal after the described laser acquisition is analyzed, and obtains the back scattering feature of the described different radii particulate of laser acquisition; And, obtain the atmospheric duct characteristic parameter according to the back scattering feature and the air index situation of change of particulate in different temperatures, humidity and the pressure environment.

6. system according to claim 5 is characterized in that, described explorer comprises:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And

Emitting antenna is used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports described processor to.

7. system according to claim 6 is characterized in that, the transadmittance gain of described wideband low noise amplifier more than 1.5GHz, the input voltage noise less than

Input current noise less than

8. system according to claim 6, it is characterized in that, described avalanche photodide biasing stepup transformer comprises: avalanche photodide, the digital temperature chip, D/A and microprocessor, wherein, described microprocessor is read current described avalanche photodide APD surface temperature value by described digital temperature chip, use the temperature-slide-back curve under the APD fixed gain, obtain the target bias V of APD under the Current Temperatures _Goal, adjust the current bias voltage V of APD by D/A _ControlTo target bias V _Goal

9. system according to claim 8 is characterized in that, the response time 450ps of described avalanche photodide, and noise current is

10. system according to claim 6 is characterized in that, described light signal receiving subsystem also has the shield assembly that utilizes weak magnetic material to make.

11. system according to claim 10 is characterized in that, described weak magnetic material is the metallic aluminium of thickness 1.3mm.

12. system according to claim 6 is characterized in that, described processor is by following formula $I_{\mathrm{sca}}=I_0\frac{{\mathrm{\&lambda;}}^2}{{8\mathrm{\&pi;}}^2{R}^2}I(\mathrm{\&theta;},\mathrm{\&phi;})$ Scattered light signal after the described laser acquisition is analyzed, obtaining the aerocolloidal back scattering of the described different radii of laser acquisition is characterized as: particulate produces the increase of back scattering light signal along with the particulate radius under the incident of laser, back scattered intensity correspondingly strengthens;

Wherein, I ₀Be the incident light intensity, λ is an optical maser wavelength, I _ScaFor with the atmosphere center O at a distance of the scattered light intensity of ordering for the P of R place,

Be the scattered light intensity relevant with angle, wherein,

Wherein, I ₁, I ₂Expression is vertical and be parallel to the scattering strength function component on scattering plane, S respectively ₁, S ₂Expression amplitude function, its infinite series form is: $S_1\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)]$

$S_2\left(\mathrm{\&theta;}\right)=\underset{n=1}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\frac{2n+1}{n(n+1)}[a_n{\mathrm{\&tau;}}_n\left(\cos \mathrm{\&theta;}\right)+b_n{\mathrm{\&pi;}}_n\left(\cos \mathrm{\&theta;}\right)]$

Wherein, a _n, b _nBe the Mie scattering coefficient, this Mie scattering coefficient is the function of the ratio parameter alpha (α=2 π r/ λ) of single particle yardstick r and laser wavelength lambda.

13. an explorer is characterized in that, comprising:

The Laser emission subsystem is used for launching laser to simulating atmospheric environment;

The light signal receiving subsystem, be used for obtaining of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Wherein, described Laser emission subsystem comprises:

Pulsed laser, being used to produce pulse energy is 20mJ, and pulse width is 10ns, and wavelength is the laser of 1.064 μ m; And

Emitting antenna is used for launching the laser of described pulsed laser generation to simulating atmospheric environment;

Wherein, described light signal receiving subsystem comprises:

Receiving antenna, be used for receiving of the different radii particulate irradiation of described laser to described simulation atmospheric environment after, the laser acquisition back scattering light signal of generation;

Detector is used for described laser acquisition back scattering light signal is surveyed, output High-speed transient faint optical signal;

Wideband low noise amplifier is used for described High-speed transient faint optical signal is amplified;

Avalanche photodide biasing stepup transformer is used to receive the High-speed transient faint optical signal of described detector output, and exports the processor that is connected with described explorer to.

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