CN103487010A - Three-ring apodization filter based system and method used for measuring isoplanatic angles - Google Patents

Abstract

The invention discloses a three-ring apodization filter based system and a method used for measuring isoplanatic angles. The three-ring apodization filter based system comprises a three-ring apodization filter. Light wave modulated by the three-ring apodization filter enters into an optical receiving system; image formation of the received light wave is realized by an optical imaging system, and then the light wave is focused on a focal plane of a photomultiplier; analog-digital conversion, collection and processing of current signals of the photomultiplier are realized by an acquisition and processing system. All-weather measurement of isoplanatic angles at different height can be realized by using the three-ring apodization filter based system and the method, relative errors of the measured isoplanatic angles are relatively small, and measurement accuracy is relatively higher than that of existing isoplanatic angle measuring systems in domestic.

Description

A kind of dizzy angle measuring system such as grade and method based on three ring apodization mirrors

Technical field

The invention belongs to the atmospheric optics technical field, relate to a kind of dizzy angle measuring system such as grade and method based on three ring apodization mirrors.

Background technology

When light wave transmits in atmosphere, due to the impact of atmospheric turbulence, the corrugated of light wave meeting distorted, intensity can produce fluctuating.Transmission for the light wave that comprises laser in real atmosphere, atmospheric turbulence causes the random deviation of beam Propagation direction, the expansion of light beam and the random fluctuation of intensity, thereby affects the application of the optical engineering such as laser.

For the ground astronomical optics, observe, when utilizing bigbore optics receiving telescope to carry out imaging to the observed object in space, send the light wave corrugated and produce distortion because atmospheric turbulence causes the spatial observation target, thereby cause the decrease resolution of optical telescope, affect observation effect.Generally speaking, when there is no the affecting of atmospheric turbulence, the resolution of the optical telescope that bore is D is 1.22 λ/D, and wherein λ is that the received light wave-wave is long; And, for actual conditions, always have the impact of atmospheric turbulence, now, the resolution of optical telescope can be reduced to 1.22 λ/r ₀, r wherein ₀for describing the parameter-atmospheric coherence length of whole atmosphere turbulence characteristics.The optical telescope aperture of observing for astronomical optics at present is roughly all more than 1m, and the numerical value of whole atmosphere coherent length is generally the scope of several centimetres to ten several centimetres, but, impact due to atmospheric turbulence, in the situation that do not have adaptive optics to proofread and correct, the telescope of the telescopical resolution of heavy caliber and tens of centimetres of bores is suitable.So atmospheric turbulence has comparatively serious restriction to bigbore optical telescope imaging resolution.

In order to improve the transmission performance of the light wave such as laser in atmosphere, to improve the telescopical resolution of heavy caliber, can utilize adaptive optics to proofread and correct the corrugated that atmospheric turbulence is caused and differ and is proofreaied and correct.And the adaptive optics timing, if the beacon light wave is inconsistent with the transmission direction of proofreading and correct light wave, for example, while having certain angle, the corrugated due to the beacon light wave differs the turbulence characteristics that can not represent fully on needs correction light path, so, utilize adaptive optics to carry out timing and can have certain corrugated residual error, and the corrugated residual error caused thus is relevant to the angle of the transmission direction of beacon light wave and correction light wave.

Mean etc. dizzy angle the maximum angle that corrugated is relevant, when beacon light wave and the angle of proofreading and correct the light wave transmissions direction such as are greater than at the dizzy angle, the turbulent characteristics that corrugated of beacon light wave differs on the light path of proofreading and correct with needs is fully uncorrelated, now, utilize adaptive optics effectively to be proofreaied and correct the impact of atmospheric turbulence.So waiting dizzy angle is one of important parameter atmospheric turbulence effect carried out the required consideration of adaptive optics timing.

If the atmospheric turbulence intensity along z place on light path is C _n ²(z), wait dizzy angle θ ₀for

Wherein k=2 π/λ is the light wave wave number, and λ is optical wavelength;

for zenith angle.As can be seen from the above equation, wait dizzy angle θ ₀for atmospheric turbulence intensity C _n ²(z) weighting function, wherein weight function is z ^5/3.And the starlight intensity normalization fluctuating variances sigma of utilizing telescope to receive _s ²for

Wherein A=2 π ∫ ρ P (ρ) d ρ is the annulus glazed area.By above two formula, can be found out, if can make weighting function W (z) in formula (2)=cz ^5/3, can utilize measured starlight intensity fluctuation variances sigma _s ²inverting such as provides at the dizzy angle.

Be mainly used in the measurement at the dizzy angles such as atmospheric optical parameters etc. dizzy angle measuring instrument, and one of its crucial measuring element is the apodization mirror.From the end of the seventies in last century, after Loos and Hogge propose the concept of apodization mirror, Walters has designed single-orifice type apodization mirror in nineteen eighty-three, and in 1985, that it is perfect, has designed the apodization mirror of twin nuclei, the measuring accuracy at dizzy angle such as has improved.Within 1988, USAF has successfully designed the apodization mirror of tricyclic structure in Lincoln testing laboratory, and its measurement result can reach very high precision under weak turbulent-flow conditions.The domestic unit that carries out this area research work mainly comprises Chinese Academy of Sciences's Nation Astronomical Observatory and Anhui ray machine institute, its technical merit roughly is equivalent to U.S. 1980s level, still use single aperture apodization mirror, in the comparatively elementary stage, measuring accuracy is lower, the needs of adaptive optics compensation effect assessment in the time of can not meeting astronomical optics site selection and light wave fully and transmit in actual turbulent atmosphere.

Summary of the invention

The problem that the present invention solves is to provide a kind of dizzy angle measuring system such as grade and method based on three ring apodization mirrors, this system is by measuring the starlight intensity fluctuation after propagation in atmosphere, can be good at simulating the aperture filter function, obtain the dizzy angle such as grade along measuring route, realize the high-acruracy survey at the dizzy angle of equity.

The present invention is achieved through the following technical solutions:

A kind of dizzy angle measuring system such as grade based on three ring apodization mirrors, comprise three ring apodization mirrors, light wave through three ring apodization mirror modulation is incident to optical receiving system, by optical imaging system by received light wave imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier;

Described optical receiving system comprises astronomical telescope and collimation lens, after the light wave incident astronomical telescope of three ring apodization mirror modulation, then is emitted to optical imaging system by collimation lens;

Described optical imaging system is provided with attenuator, optical filter, spectroscope and imaging len on light path;

Described photomultiplier is driven by supporting high-voltage power supply;

Described data Collection & Processing System comprises A/D converter, data collecting card and calculation processing unit, photomultiplier amplifies signal output electrical signals, A/D converter is that digital signal sends to calculation processing unit through data collecting card by analog signal conversion, calculation processing unit reads digital signal, treatedly the dizzy angle such as obtains.

Further, also comprise image monitoring system, the spectroscope in optical imaging system is divided into two parts by light beam, and a part is incident on photomultiplier, and another part is transmitted to image monitoring system;

Described image monitoring system comprises CCD camera and display, after optical imaging system emission light beam, images on the CCD camera, and shows on display.

Further, also comprise control system, control system connects respectively astronomical telescope, CCD camera and data Collection & Processing System, trace routine by astronomical telescope is controlled the open-loop tracking of astronomical telescope to Celestial Objects, utilizes the image information of CCD camera to communicate by letter with astronomical telescope and realizes the closed loop tracking; Control system also returns to data Collection & Processing System by telescopical zenith angle real time data, the dizzy angle Inversion Calculation such as supplies to analyze reference.

In described optical imaging system, attenuator is regulated the light intensity of incident light, prevents that photomultiplier is saturated, and optical filter improves system signal noise ratio; And spectroscope is divided into two parts by light beam, a part is incident on photomultiplier, and another part is imaged on the CCD camera, is convenient to system light path and regulates and astronomical telescope is followed the tracks of to control.

Described attenuator is narrow band pass filter, the plated film attenuator that described attenuator is wiping out background light.

Described astronomical telescope returns to data Collection & Processing System the zenith angle φ that fixed star light source position becomes with the measurement place by gps data in real time _z.

Described three ring apodization mirrors, be comprised of concentric, light tight annulus alternative arrangement and printing opacity annulus, and the printing opacity annulus is followed successively by interior ring, adapter ring and outer shroud from inside to outside, wherein in the ring least radius be 37.389mm, maximum radius is 43.840mm; The adapter ring least radius is 62.890mm, and maximum radius is 69.240mm; The outer shroud least radius is 81.940mm, and maximum radius is 101.600mm; The transmitance of described light tight annulus is not more than 1%, and the transmitance of printing opacity annulus is not less than 99.0%; This three rings apodization mirror simulation aperture filter function W (z) ≡ cz ^5/3the time, its aperture filter function coefficient c=8.847e-17m ⁴.

A kind of method of the dizzy angles such as dizzy angle measuring system measurement such as grade based on three ring apodization mirrors comprises following operation:

The light wave of the target celestial body transmitted through turbulent atmosphere, be incident to optical receiving system after the apodization mirror, by the optical imaging system imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier, and last inverting such as provides at the dizzy angular measurement result;

Wherein the penetrating light intensity distribution functions of three ring apodization mirrors are P (ρ), light transmission part P (ρ)=1, and lightproof part P (ρ)=0, ρ is the radial distance of annulus, and the total light intensity by the apodization mirror is denoted as S, and S is time variable; Atmospheric turbulence can cause the starlight intensity fluctuation after transmission, by its normalization, by formula (3), provides the light intensity fluctuation variance:

${\mathrm{\&sigma;}}_s^2({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})={4\left(2\mathrm{\&pi;}\right)}^4{0.033\mathrm{<figure-callout\; id="8"\; label="sec"\; filenames="HDA00003456940500051.png"\; state="\{\{state\}\}">sec</figure-callout>}}^{8/3}{\left({\mathrm{\&phi;}}_z\right)k}^2{A}^{-2}{\&Integral;}_0^{\&infin;}{C}_n^2\left(z\right)W\left(z\right)\mathrm{dz}---\left(3\right)$

A=2 π ∫ ρ P (ρ) d ρ wherein; K[=2 π/λ] be the light wave wave number, λ is optical wavelength; φ _zfor zenith angle; Z is the telescopical distance of distance on astronomical telescope and target celestial body light path; C _n ²(z) be the air index textural constant at distance z place; The representation of weighting function W (z) as shown in the formula:

$W\left(z\right)={\&Integral;}_0^{\&infin;}{|\&Integral;\mathrm{d\&rho;\&rho;}{J}_0\left(\mathrm{L\&rho;}\right)P\left(\mathrm{L\&rho;}\right)|}^2{L}^{-8/3}{\sin }^2\left[\frac{L^{2}z}{2k}\right]\mathrm{dL}---\left(4\right)$

J in formula ₀(x) be zeroth order Bessel function; The spatial frequency that K is amplitude fluctuation, K _max=2 π/l ₀, K _min=2 π/L ₀, l ₀, L ₀be respectively yardstick and external measurement in atmospheric turbulence; The aperture function that P (ρ) is the apodization mirror, light transmission part P (ρ)=1 wherein, lightproof part P (ρ)=0, ρ is the radial distance (radius) of annulus;

Normalization light intensity fluctuation variance is zenith angle φ _zwith the function of incident wavelength λ, its scope of application is that light intensity fluctuation meets weak fluctuation condition, when normalization light intensity fluctuation variances sigma _s ²(φ _z, λ) during unsaturation, think etc. that dizzy angular measurement result is effective;

Dizzy angle such as grade along measuring route z is provided by formula (5):

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=0.527k^{-6/5}{\left[{\&Integral;}_0^{\&infin;}{C}_n^2{\left(z\right)z}^{5/3}\mathrm{dz}\right]}^{-3/5}---\left(5\right)$

Can show etc. that in conjunction with equation (3) and equation (5) dizzy angle computing formula is:

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=12.9A^{-6/5}{\mathrm{<figure-callout\; id="3"\; label="c"\; filenames="DEST\_PATH\_HDA0000403219690000042.png"\; state="\{\{state\}\}">c</figure-callout>}}^{3/5}{\left[{\mathrm{\&sigma;}}_s^2\left({\mathrm{\&phi;}}_z\right)\right]}^{-3/5}---\left(6\right)$

Wherein, the c value can be by W (z) ≡ cz ^5/3matching provides numerical solution.

Described when normalization light intensity fluctuation variance, σ _s ²(0) be calculated as follows:

${\mathrm{\&sigma;}}_s^2\left(0\right)=\frac{\mathrm{variance}}{{\mathrm{mean}}^2}=\frac{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left[{\mathrm{\&alpha;X}}_i\right]}^2-{\left[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i\right]}^2}{{[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i-b]}^2}---\left(8\right)$

Wherein, the gain coefficient that α is photomultiplier; The background value that b measures while being the gauge without light source signal, obtain by repeatedly measuring the method that the institute's fixed star of surveying bias light on every side averages;

And the zenith angle φ that target celestial body light source position becomes with the measurement place _z, by gps data, from astronomical telescope, return in real time.

The sample frequency of the dizzy angle measuring system such as grade of described three ring apodization mirrors is f, and waiting the sample size of dizzy angular measurement is N, and sampling time t=N/f is set, i.e. every value through a dizzy angle such as grade of t Time Calculation; So that sample size N to be set, often adopt enough N data, just once calculate, obtain and export the dizzy angle value such as.

Compared with prior art, the present invention has following useful technique effect:

A kind of dizzy angle measuring system such as grade and method based on three ring apodization mirrors provided by the invention, the apodization mirror of employing tricyclic structure, can obtain higher measuring accuracy; Utilize long wave pass filter to coordinate the dizzy angles such as photomultiplier measurement, can realize daytime measurement; Therefore the present invention can realize the dizzy angles such as daytime measurement at all height, and the dizzy angle such as gained relative error is less, and the measuring accuracy of comparing with dizzy angle measuring system such as domestic existing grade is higher.

A kind of dizzy angle measuring system such as grade and method based on three ring apodization mirrors provided by the invention, with respect to single aperture apodization mirror, can well simulate aperture filter function W (z) ≡ cz at all height ^5/3, the dizzy angle such as gained relative error is obviously less, can realize the high-acruracy survey at the dizzy angle of equity, and maximum relative error is no more than 3%.

The accompanying drawing explanation

The dizzy angle measuring system principle schematic such as Fig. 1 is;

Fig. 2 such as is at the dizzy angle measuring system composition frame chart;

Fig. 3 such as is at the dizzy angle measuring system overall layout chart;

Fig. 4 such as is at the overall index path of dizzy angle measuring system;

The structural representation that Fig. 5 is three ring apodization mirrors; Wherein, 1 is outer shroud, and 2 is adapter ring, and 3 is interior ring;

Fig. 6 is two kinds of apodization mirror aperture filter functions and " z ^5/3" power weighting function consistance comparison chart;

Fig. 7 is the two kinds of analog weighted function relative error of apodization mirror comparison charts;

Fig. 8 is that the theoretical computational data of three ring apodization mirrors and matched curve are compared;

Fig. 9 is that three ring apodization mirror relative errors are with the height change curve;

The measurement instruction flow chart that Figure 10 is data Collection & Processing System;

Figure 11 the dizzy angle relative error comparison chart such as is surveyed by the dizzy angle measuring system such as grade of three ring apodization mirrors.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in further detail, and the explanation of the invention is not limited.

Light wave is after propagation in atmosphere, and atmospheric turbulence can cause the random fluctuation of light wave intensity.For the starlight light wave after the apodization mirror through particular design transmission, its intensity fluctuation with etc. dizzy angle there is certain relation, so, by measuring the fluctuating of starlight intensity, can provide dizzy angle such as needed grade.

Referring to Fig. 1, wait dizzy angle measuring system principle to be: starlight, after the turbulent atmosphere transmission, by the modulation of apodization mirror, focuses to photodetector.Its light intensity fluctuation with etc. dizzy angle definite relation is arranged, by measuring the intensity fluctuation of starlight, the dizzy angle such as can inverting provide.

Referring to Fig. 2, Fig. 3, Fig. 4, dizzy angle measuring system such as grade based on three ring apodization mirrors provided by the invention, comprise three ring apodization mirrors, light wave through three ring apodization mirror modulation is incident to optical receiving system, by optical imaging system by received light wave imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier;

Described optical receiving system comprises astronomical telescope and collimation lens, after the light wave incident astronomical telescope of three ring apodization mirror modulation, then is emitted to optical imaging system by collimation lens;

Described optical imaging system is provided with attenuator, optical filter, spectroscope and imaging len on light path;

Described photomultiplier is driven by supporting high-voltage power supply;

Described data Collection & Processing System comprises A/D converter, data collecting card and calculation processing unit, photomultiplier amplifies signal output electrical signals, A/D converter is that digital signal sends to calculation processing unit through data collecting card by analog signal conversion, calculation processing unit reads digital signal, treatedly the dizzy angle such as obtains.

Further, also comprise image monitoring system, the spectroscope in optical imaging system is divided into two parts by light beam, and a part is incident on photomultiplier, and another part is transmitted to image monitoring system;

Described image monitoring system comprises CCD camera and display, after optical imaging system emission light beam, images on the CCD camera, and shows on display.

Further, also comprise control system, control system connects respectively astronomical telescope, CCD camera and data Collection & Processing System, trace routine by astronomical telescope is controlled the open-loop tracking of astronomical telescope to Celestial Objects, utilizes the image information of CCD camera to communicate by letter with astronomical telescope and realizes the closed loop tracking; Control system also returns to data Collection & Processing System by telescopical zenith angle real time data, the dizzy angle Inversion Calculation such as supplies to analyze reference.

Be specifically described and introduce below in conjunction with each system.

1, three ring apodization mirrors

Etc. dizzy angle, be the weighted integral of air index textural constant, " 5/3 " power function that wherein weighting function is distance.In order to utilize hardware to realize " 5/3 " the power weighting function to height, need designed apodization mirror can simulate well W (z) ≡ cz ^5/3requirement.At present comparatively generally mainly containing three kinds of apodization mirrors, is respectively single hole apodization mirror, and dicyclo apodization mirror and three ring apodization mirrors also are not quite similar to the capability of fitting of " 5/3 " power of height.Wherein, the capability of fitting of the apodization mirror of tricyclic structure is much better than the apodization mirror of single hole structure and twin nuclei, and its fitting coefficient c value can reflect the weighting function of " 5/3 " power preferably at the height of 300m to 30000m.

Referring to Fig. 5, the three ring apodization mirrors that the present invention adopts, be comprised of concentric, light tight annulus alternative arrangement and printing opacity annulus, and the printing opacity annulus is followed successively by interior ring, adapter ring and outer shroud from inside to outside, wherein, the ring least radius is 37.389mm, and maximum radius is 43.840mm; The adapter ring least radius is 62.890mm, and maximum radius is 69.240mm; The outer shroud least radius is 81.940mm, and maximum radius is 101.600mm; The transmitance of described light tight annulus is not more than 1%, and the transmitance of printing opacity annulus is not less than 99.0%; This three rings apodization mirror simulation aperture filter function W (z) ≡ cz ^5/3the time, its aperture filter function coefficient c=8.847e-17m ⁴.

Aperture filter function and z that Fig. 6 is three ring apodization mirrors and single hole apodization mirror ^5/3ratio is with the variation relation of height.Can find out, under wavelength and the certain condition of zenith angle, the aperture filter function of single aperture apodization mirror, at all height, can not be simulated shape as " z well ^5/3" weighting function, be inferior to three ring apodization mirrors.As optical wavelength λ=0.5 μ m, zenith angle is 0 °, interior yardstick l ₀=5mm, external measurement L ₀during=10m, single aperture apodization mirror is compared with the ring of three in the present invention apodization mirror, aperture filter function and z ^5/3consistance poor, the dizzy angle such as gained relative error is larger.

Atmospheric turbulence profile model has multiple, and wherein the H-V model is a kind of atmospheric turbulence profile model commonly used.Utilize air index textural constant profile model (H-V model) commonly used to bring (2) formula into, the relative error such as dizzy angle such as grade that calculating provides two kinds of apodization mirror gained as shown in Figure 7, obviously can find out, the relative error of three ring apodization mirrors is less than the relative error of single hole apodization mirror.

Concrete when wavelength X=0.5 μ m, wait the expression formula of dizzy angle and light intensity fluctuation variance to be:

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=c^{\&prime;}{\left[{\mathrm{\&sigma;}}_s^2\left({\mathrm{\&phi;}}_z\right)\right]}^{-3/5}---\left(7\right)$

Calculate the curve of W (z) as shown in Figure 8, the number percent curve of both differences as shown in Figure 9.

As can be seen here, use this apodization mirror can realize the modulation to light signal, meet etc. in dizzy angular measurement principle the requirement to light distribution.Its method for making can adopt the mode to eyeglass plating circular membrane to realize.

Method one:

The preparation method of three ring apodization mirrors, is characterized in that, comprises following operation:

On the circular substrate that be not less than 99.0% in transmitance, radius is 101.600mm, take its center of circle as benchmark, at first pasting radius is the light tight round metal of 37.389mm, and then the stickup least radius is the light tight metal ring that 43.840mm, maximum radius are 62.890mm; Finally pasting least radius is the light tight metal ring that 69.240mm, maximum radius are 81.940mm again.

Wherein, substrate is to utilize the window materials such as K9 glass, plexiglas or quartz to make the transparent substrate that radius is 101.600mm.

Method two:

The preparation method of three ring apodization mirrors comprises following operation:

1) circular below making on substrate: as to take central point as the center of circle, portray respectively the first circle, the second circle, the 3rd circle, the 4th circle, the 5th circular and the 6th circle that radius is respectively 37.389mm, 43.840mm, 62.890mm, 69.240mm, 81.940mm and 101.600mm;

Annulus between annulus, the 4th circle and the 5th circle of 2) usining between the first circle, the second circle and the 3rd circle is as lightproof part;

Annulus between annulus, the 5th circle and the 6th circle between annulus, the 3rd circle and the 4th circle of usining between the first circle and the second circle is as light transmission part;

Utilize mask plate that lightproof part is blocked, plate respectively transmitance on two surfaces, light transmission part of substrate and be not less than 99.0% anti-reflection film; Then with mask plate, light transmission part is blocked, on lightproof part two surfaces of substrate, plate respectively and increase reverse, make its transmitance be not more than 1%.

2, optical receiving system

This system mainly is comprised of astronomical telescope and collimation lens.Wherein telescope intends selecting the CGEM800GPS XLT type astronomical telescope of Xing Telang company; Collimation lens and astronomical telescope system are confocal, its role is to the direction of focused beam is adjusted, and make its normal incidence on optical filter, improve the filter effect of optical filter.Its mirror holder part need to be complementary with astronomical telescope, can entrust relevant unit to carry out precision optical machinery processing.

3, optical imaging system

This system mainly is comprised of attenuator, optical filter, spectroscope and imaging len.Wherein the light intensity of attenuator for regulating incident light, prevent that photomultiplier is saturated, and optical filter is for improving system signal noise ratio.Spectroscope is divided into two parts by light beam, and a part is incident on photomultiplier, and it is upper that another part is imaged on CCD, is convenient to the system light path adjusting and telescope is carried out to closed loop and follow the tracks of control.

4, photomultiplier

Mainly by photomultiplier and supporting high-voltage power supply, formed, specifically can adopt the 9128B of ET company.

5, image monitoring system

Mainly by CCD camera and display, formed.Its Main Function be while regulating for system state with reference to so that operating personnel grasp the telescopic system state, understand the system imaging quality, differentiate and whether can start to measure.

6, data Collection & Processing System

Data Collection & Processing System mainly is comprised of A/D converter, data collecting card and computing software.Photomultiplier amplifies low light level signal, and output electrical signals, and A/D converter is that digital signal is stored in calculator memory through data collecting card by analog signal conversion, and software for calculation reads the signal data in internal memory, processes the value at dizzy angles such as obtaining.

Referring to Figure 10, data Collection & Processing System mainly comprises: a), real-time data acquisition; B), signal de-noising; C), light intensity is calculated; D), the light intensity fluctuation variance is calculated; The dizzy angle inverting such as e); F), data Storage & Display.

7, control system

Control system connects astronomical telescope, CCD camera and data acquisition processing system.Utilize the telescopic system database to realize the open-loop tracking to Celestial Objects (fixed star) by controlling software, use the image information of CCD camera to realize the closed loop tracking.Transmitting software the dizzy angle computing software such as returns to by telescopical zenith angle (elevation angle) real time data, for the computational analysis reference.

Below provide the method at the dizzy angles such as dizzy angle measuring system measurement such as grade based on three ring apodization mirrors, it is characterized in that, comprise following operation:

The light wave of the target celestial body transmitted through turbulent atmosphere, be incident to optical receiving system after the apodization mirror, by the optical imaging system imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier, and last inverting such as provides at the dizzy angular measurement result;

Wherein the penetrating light intensity distribution functions of three ring apodization mirrors are P (ρ), light transmission part P (ρ)=1, and lightproof part P (ρ)=0, ρ is the radial distance of annulus, and the total light intensity by the apodization mirror is denoted as S, and S is time variable; Atmospheric turbulence can cause the starlight intensity fluctuation after transmission, by its normalization, by formula (3), provides the light intensity fluctuation variance:

${\mathrm{\&sigma;}}_s^2({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})={4\left(2\mathrm{\&pi;}\right)}^4{0.033\mathrm{<figure-callout\; id="8"\; label="sec"\; filenames="HDA00003456940500051.png"\; state="\{\{state\}\}">sec</figure-callout>}}^{8/3}{\left({\mathrm{\&phi;}}_z\right)k}^2{A}^{-2}{\&Integral;}_0^{\&infin;}{C}_n^2\left(z\right)W\left(z\right)\mathrm{dz}---\left(3\right)$

A=2 π ∫ ρ P (ρ) d ρ wherein; K[=2 π/λ] be the light wave wave number, λ is optical wavelength; φ _zfor zenith angle; Z is the telescopical distance of distance on astronomical telescope and target celestial body light path; C _n ²(z) be the air index textural constant at distance z place; The representation of weighting function W (z) as shown in the formula:

$W\left(z\right)={\&Integral;}_0^{\&infin;}{|\&Integral;\mathrm{d\&rho;\&rho;}{J}_0\left(\mathrm{L\&rho;}\right)P\left(\mathrm{L\&rho;}\right)|}^2{L}^{-8/3}{\sin }^2\left[\frac{L^{2}z}{2k}\right]\mathrm{dL}---\left(4\right)$

J in formula ₀(x) be zeroth order Bessel function; The spatial frequency that K is amplitude fluctuation, K _max=2 π/l ₀, K _min=2 π/L ₀, l ₀, L ₀be respectively yardstick and external measurement in atmospheric turbulence; The aperture function that P (ρ) is the apodization mirror, light transmission part P (ρ)=1 wherein, lightproof part P (ρ)=0, ρ is the radial distance (radius) of annulus;

Normalization light intensity fluctuation variance is zenith angle φ _zwith the function of incident wavelength λ, its scope of application is that light intensity fluctuation meets weak fluctuation condition, when normalization light intensity fluctuation variances sigma _s ²(φ _z, λ) during unsaturation, think etc. that dizzy angular measurement result is effective;

Dizzy angle such as grade along measuring route z is provided by formula (5):

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=0.527k^{-6/5}{\left[{\&Integral;}_0^{\&infin;}{C}_n^2{\left(z\right)\mathrm{<figure-callout\; id="5"\; label="z"\; filenames="DEST\_PATH\_HDA0000403219690000041.png,DEST\_PATH\_HDA0000403219690000061.png"\; state="\{\{state\}\}">z</figure-callout>}}^{5/3}\mathrm{dz}\right]}^{-3/5}---\left(5\right)$

Can show etc. that in conjunction with equation (3) and equation (5) dizzy angle computing formula is:

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=12.9A^{-6/5}{\mathrm{<figure-callout\; id="3"\; label="c"\; filenames="DEST\_PATH\_HDA0000403219690000042.png"\; state="\{\{state\}\}">c</figure-callout>}}^{3/5}{\left[{\mathrm{\&sigma;}}_s^2\left({\mathrm{\&phi;}}_z\right)\right]}^{-3/5}---\left(6\right)$

Wherein, the c value can be by W (z) ≡ cz ^5/3matching provides numerical solution.

And when normalization light intensity fluctuation variance, σ _s ²(0) be calculated as follows:

${\mathrm{\&sigma;}}_s^2\left(0\right)=\frac{\mathrm{variance}}{{\mathrm{mean}}^2}=\frac{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left[{\mathrm{\&alpha;X}}_i\right]}^2-{\left[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i\right]}^2}{{[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i-b]}^2}---\left(8\right)$

Wherein, the gain coefficient that α is photomultiplier; The background value that b measures while being the gauge without light source signal, obtain by repeatedly measuring the method that the institute's fixed star of surveying bias light on every side averages;

And the zenith angle φ that target celestial body light source position becomes with the measurement place _z, by gps data, from astronomical telescope, return in real time.

Wherein, the sample frequency of the dizzy angle measuring system such as grade of three ring apodization mirrors are f, according to etc. the index request of dizzy angle measuring system, sample size is N, and sampling time t=N/f can be set in software, i.e. every value through a dizzy angle such as grade of t Time Calculation.Also sample size N can be set, often adopt enough N data, just once calculate, obtain and export the dizzy angle value such as.In the situation that not frame losing of system acquisition, ft=N, if can not guarantee the not frame losing continuously of N frame data, can cause ft<N, therefore, enough in order to guarantee data volume, preferentially selects sample size N that the value at the dizzy angles such as calculating is set.

Referring to Figure 11, provided the variation contrast of the relative error of the dizzy angle measuring system measurement such as grade based on three ring apodization mirrors with height in figure.Can find out, the weighting function relative error of the dizzy angle measuring system such as grade of three ring apodization mirrors is at 0.5～20km distance range, and maximum relative error is no more than 3%, and the relative error of monocycle apodization mirror can reach 15%.The visible precision at the dizzy angles such as three ring apodization mirror measurements of utilizing is significantly improved.

Claims (10)

1. the dizzy angle measuring system such as grade based on three ring apodization mirrors, it is characterized in that, comprise three ring apodization mirrors, light wave through three ring apodization mirror modulation is incident to optical receiving system, by optical imaging system by received light wave imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier;

Described optical receiving system comprises astronomical telescope and collimation lens, after the light wave incident astronomical telescope of three ring apodization mirror modulation, then is emitted to optical imaging system by collimation lens;

Described optical imaging system is provided with attenuator, optical filter, spectroscope and imaging len on light path;

Described photomultiplier is driven by supporting high-voltage power supply;

Described data Collection & Processing System comprises A/D converter, data collecting card and calculation processing unit, photomultiplier amplifies signal output electrical signals, A/D converter is that digital signal sends to calculation processing unit through data collecting card by analog signal conversion, calculation processing unit reads digital signal, treatedly the dizzy angle such as obtains.

2. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 1, it is characterized in that, also comprise image monitoring system, the spectroscope in optical imaging system is divided into two parts by light beam, a part is incident on photomultiplier, and another part is transmitted to image monitoring system;

Described image monitoring system comprises CCD camera and display, after optical imaging system emission light beam, images on the CCD camera, and shows on display.

3. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 2, it is characterized in that, also comprise control system, control system connects respectively astronomical telescope, CCD camera and data Collection & Processing System, trace routine by astronomical telescope is controlled the open-loop tracking of astronomical telescope to Celestial Objects, utilizes the image information of CCD camera to communicate by letter with astronomical telescope and realizes the closed loop tracking; Control system also returns to data Collection & Processing System by telescopical zenith angle real time data, the dizzy angle Inversion Calculation such as supplies to analyze reference.

4. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 2, is characterized in that, in described optical imaging system, attenuator is regulated the light intensity of incident light, prevents that photomultiplier is saturated, and optical filter improves system signal noise ratio; And spectroscope is divided into two parts by light beam, a part is incident on photomultiplier, and another part is imaged on the CCD camera, is convenient to system light path and regulates and astronomical telescope is followed the tracks of to control.

5. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 4, is characterized in that, described attenuator is narrow band pass filter, the plated film attenuator that described attenuator is wiping out background light.

6. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 1, is characterized in that, described astronomical telescope returns to data Collection & Processing System the zenith angle φ that fixed star light source position becomes with the measurement place by gps data in real time _z.

7. the dizzy angle measuring system such as grade based on three ring apodization mirrors as claimed in claim 1, it is characterized in that, described three ring apodization mirrors, by concentric, light tight annulus alternative arrangement and printing opacity annulus, formed, the printing opacity annulus is followed successively by interior ring, adapter ring and outer shroud from inside to outside, wherein, the ring least radius is 37.389mm, and maximum radius is 43.840mm; The adapter ring least radius is 62.890mm, and maximum radius is 69.240mm; The outer shroud least radius is 81.940mm, and maximum radius is 101.600mm; The transmitance of described light tight annulus is not more than 1%, and the transmitance of printing opacity annulus is not less than 99.0%; This three rings apodization mirror simulation aperture filter function W (z) ≡ cz ^5/3the time, its aperture filter function coefficient c=8.847e-17m ⁴.

8. the method at the dizzy angles such as dizzy angle measuring system measurement such as grade based on three ring apodization mirrors, is characterized in that, comprises following operation:

The light wave of the target celestial body transmitted through turbulent atmosphere, be incident to optical receiving system after the apodization mirror, by the optical imaging system imaging and focusing on the focal plane of photomultiplier, data Collection & Processing System carries out analog to digital conversion, acquisition and processing to the current signal of photomultiplier, and last inverting such as provides at the dizzy angular measurement result;

Wherein the penetrating light intensity distribution functions of three ring apodization mirrors are P (ρ), light transmission part P (ρ)=1, and lightproof part P (ρ)=0, ρ is the radial distance of annulus, and the total light intensity by the apodization mirror is denoted as S, and S is time variable; Atmospheric turbulence can cause the starlight intensity fluctuation after transmission, by its normalization, by formula (3), provides the light intensity fluctuation variance:

${\mathrm{\&sigma;}}_s^2({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})={4\left(2\mathrm{\&pi;}\right)}^4{0.033\sec }^{8/3}{\left({\mathrm{\&phi;}}_z\right)k}^2{A}^{-2}{\&Integral;}_0^{\&infin;}{C}_n^2\left(z\right)W\left(z\right)\mathrm{dz}---\left(3\right)$

A=2 π ∫ ρ P (ρ) d ρ wherein; K[=2 π/λ] be the light wave wave number, λ is optical wavelength; φ _zfor zenith angle; Z is the telescopical distance of distance on astronomical telescope and target celestial body light path; C _n ²(z) be the air index textural constant at distance z place; The representation of weighting function W (z) as shown in the formula:

$W\left(z\right)={\&Integral;}_0^{\&infin;}{|\&Integral;\mathrm{d\&rho;\&rho;}{J}_0\left(\mathrm{L\&rho;}\right)P\left(\mathrm{L\&rho;}\right)|}^2{L}^{-8/3}{\sin }^2\left[\frac{L^{2}z}{2k}\right]\mathrm{dL}---\left(4\right)$

J in formula ₀(x) be zeroth order Bessel function; The spatial frequency that K is amplitude fluctuation, K _max=2 π/l ₀, K _min=2 π/L ₀, l ₀, L ₀be respectively yardstick and external measurement in atmospheric turbulence; The aperture function that P (ρ) is the apodization mirror, light transmission part P (ρ)=1 wherein, lightproof part P (ρ)=0, ρ is the radial distance (radius) of annulus;

Normalization light intensity fluctuation variance is zenith angle φ _zwith the function of incident wavelength λ, its scope of application is that light intensity fluctuation meets weak fluctuation condition, when normalization light intensity fluctuation variances sigma _s ²(φ _z, λ) during unsaturation, think etc. that dizzy angular measurement result is effective;

Dizzy angle such as grade along measuring route z is provided by formula (5):

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=0.527k^{-6/5}{\left[{\&Integral;}_0^{\&infin;}{C}_n^2{\left(z\right)z}^{5/3}\mathrm{dz}\right]}^{-3/5}---\left(5\right)$

Can show etc. that in conjunction with equation (3) and equation (5) dizzy angle computing formula is:

${\mathrm{\&theta;}}_0({\mathrm{\&phi;}}_z,\mathrm{\&lambda;})=12.9A^{-6/5}{c}^{3/5}{\left[{\mathrm{\&sigma;}}_s^2\left({\mathrm{\&phi;}}_z\right)\right]}^{-3/5}---\left(6\right)$

Wherein, the c value can be by W (z) ≡ cz ^5/3matching provides numerical solution.

9. the method at the dizzy angles such as dizzy angle measuring system measurement such as grade based on three ring apodization mirrors as claimed in claim 8, is characterized in that, when normalization light intensity fluctuation variance, and σ _s ²(0) be calculated as follows:

${\mathrm{\&sigma;}}_s^2\left(0\right)=\frac{\mathrm{variance}}{{\mathrm{mean}}^2}=\frac{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\left[{\mathrm{\&alpha;X}}_i\right]}^2-{\left[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i\right]}^2}{{[\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{\&alpha;X}}_i-b]}^2}---\left(8\right)$

Wherein, the gain coefficient that α is photomultiplier; The background value that b measures while being the gauge without light source signal, obtain by repeatedly measuring the method that the institute's fixed star of surveying bias light on every side averages;

And the zenith angle φ that target celestial body light source position becomes with the measurement place _z, by gps data, from astronomical telescope, return in real time.

10. the method at the dizzy angles such as dizzy angle measuring system measurement such as grade based on three ring apodization mirrors as claimed in claim 8, it is characterized in that, the sample frequency of the dizzy angle measuring system such as grade of three ring apodization mirrors is f, sample size etc. dizzy angular measurement is N, sampling time t=N/f is set, i.e. every value through a dizzy angle such as grade of t Time Calculation; So that sample size N to be set, often adopt enough N data, just once calculate, obtain and export the dizzy angle value such as.

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