CN105572690A - Double-frequency coherent wind lidar based on single-frequency continuous light EOM modulation - Google Patents

Abstract

The invention discloses a double-frequency coherent wind lidar based on single-frequency continuous light EOM modulation. The double-frequency coherent wind lidar adopts dual-wavelength laser as a light source, and detects difference of dual-wavelength Doppler frequency shifts through coherent beat frequency to invert speed; and meanwhile, Doppler frequency shift information is extracted by adopting a microwave signal, thereby reducing speckle noise due to detection object unevenness and atmosphere turbulence. Besides, two side frequencies are generated through a single-frequency continuous wave EOM modulation method; double-frequency laser is generated through a method of utilizing a filter to filter center light frequency and filter out the two side frequencies; and the double-frequency laser generation method improves stability of a double-frequency gap, and the double-frequency gap can be controlled flexibly by adjusting trigger signals of modulators. According to the scheme, the dual-wavelength laser is obtained through single-frequency continuous wave EOM modulation, the speed is extracted through a microwave mode, and atmosphere wind speed information is inverted; the stability of the double-frequency gap is improved; and the double-frequency coherent wind lidar has the advantages of high detection precision, anti-electromagnetic interference and compact structure and the like.

Description

A kind of double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM

Technical field

The present invention relates to laser radar and survey wind field, particularly relate to a kind of double frequency continuous light coherent wind laser radar based on Laser Modulation.

Background technology

The advantages such as laser radar is high with its good directionality, temporal resolution and spatial resolution, precision is high, noncontact (remote sensing) detection, have been widely used in surveying the fields such as wind, range finding, imaging, pollutant monitoring, survey wind, thermometric.In traditional coherent wind laser radar, single-frequency laser is divided into two, and riches all the way is mapped to the detection of a target, an other road as local oscillator light, by the speed detection of object backscatter signal and local oscillator photo-beat realize target thing frequently.Ideally, when speed one timing of object, the spectrum of acquisition is narrow linewidth, and velocity information is then extracted from Doppler shift.But in a practical situation, the phase noise that the speckle noise caused due to target surface out-of-flatness, atmospheric turbulence and the coherence of laser cause will cause the broadening of Doppler shift spectral line, thus cause velocity accuracy reduction, the detection range reduction of measurement.And in traditional microwave radar, because of microwave wavelength length compared with laser, affect less by atmospheric turbulence, but spatial resolution is also therefore lower than laser radar.

In order to reduce the impact of speckle noise, improve detection accuracy, coherent wind laser radar based on double-frequency laser is suggested, it is integrated with the advantage of coherent laser radar and traditional microwave radar, in a laser radar system, adopt double-frequency laser Shu Zuowei carrier wave, frequency difference is controlled, in microwave range, make system have spatial resolution high, the advantages such as anti-atmospheric turbulence ability is strong, and signal processing technology is flourishing.The laser of double-frequency laser radar emission comprises two frequencies, two light frequencies of the object backscatter signal detected have Doppler shift, cause beat frequency frequency displacement, according to formula Δ f=Vf/2c, (in formula, Δ f is Doppler shift, and V is detection of a target speed, and f is incident light frequency, c is the light velocity), when speed V mono-timing of object, Doppler shift Δ f is directly proportional to outgoing frequency f, and velocity information is then obtained by the difference detecting double-frequency laser Doppler frequency displacement.Therefore, double frequency coherent wind laser radar detection target is that the Doppler frequency of double-frequency laser is poor, i.e. microwave signal.Doppler measurement only depends on that optical frequency is poor, instead of optical frequency itself, therefore the target range accurately can surveying wind depends on microwave stability, instead of optical frequency stability, any optical noise (the ASE noise as image intensifer, the decay along beam path and scattering process), would not influential system performance if only change laser linewidth and do not change microwave line width.Microwave wavelength is much larger than laser, the Doppler shift broadening of spectral lines that inhibit speckle noise to cause, this greatly reduces speckle noise that atmospheric turbulence and target surface out-of-flatness cause to the impact of speed detection, and the coherent signal processing link of laser radar is transferred to the circuit part of technical development maturation from light path part, retain the advantage of laser radar high spatial resolution simultaneously, thus maximize favourable factors and minimize unfavourable ones, promote the overall performance of radar system to a great extent, shorten the R&D cycle.

In double frequency coherent wind laser radar, detection be the difference on the frequency of double-frequency laser, be generally tens GHz, suppose that frequency difference is 40GHz, then the frequency difference that the wind speed of 1m/s causes is 267Hz.Therefore, the type laser radar is harsh to the stability requirement of two laser frequency spacing, and the phase noise that laser coherence causes can cause Doppler shift broadening of spectral lines, limits its development.The coherence of microwave beat signal and stability can be strengthened by phase-locked, but are difficult by two bundle laser phase-lockeds.

At present, the laser instrument that double frequency coherent laser radar adopts has mode-locked laser and injection seeded semiconductor laser.In order to obtain bifrequency Laser output, mode-locked laser need be equipped with wavelength-selective switches or Fabry-Perot interferometer, and injection seeded semiconductor laser need be equipped with main laser and use from laser instrument, therefore, the light path based on the laser radar system of these two kinds of laser instruments is complicated, with high costs.In addition, double-frequency laser source also by the known laser beam of overlapping two frequency differences or can obtain based on laser cavity external modulation, and the former obviously can not improve the low problem of laser coherence.

Summary of the invention

The object of this invention is to provide a kind of double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM, have that precision is high, good stability and the advantage such as cost is relatively low.

The object of the invention is to be achieved through the following technical solutions:

Based on the double frequency coherent wind laser radar that single-frequency continuous light EOM modulates, comprising:

Continuous light laser instrument 1, electrooptic modulator EOM2, signal generator 3, first wave filter 4, laser amplifier 5, second wave filter 6, beam splitter 7, circulator 8, optical transmitting and receiving device 9, serial adjustable pad 11, beam splitter 12, balanced detector 13, A/D capture card 14, DSP data handling system 15 and computing machine 16, the annexation of each device is as follows:

The output terminal of continuous light laser instrument 1 is connected with the input end of EOM2, EOM2 output terminal is connected with the input end of the first wave filter 4, the control signal input end of signal generator 3 is connected with the control signal output terminal of EOM2, the output terminal of the first wave filter 4 is connected with the input end of laser amplifier 5, the output terminal of laser amplifier 5 is connected with the input end of the second wave filter 6, and the output terminal of the second wave filter 6 is connected with the input end of beam splitter 7;

Described beam splitter 7 is for being divided into two points by double-frequency laser, and wherein output terminals A exports as flashlight, and what output terminal B exported is local oscillator light; The output terminals A of beam splitter 7 is connected with the A port of circulator 8, and the output terminal B of beam splitter 7 is connected with the input end of serial adjustable pad 11,

The C end of circulator 8 is connected with the A port of beam splitter 12; The B port of circulator 8 is connected with optical transmitting and receiving device 9, the light beam irradiation of optical transmitting and receiving device 9 outgoing is on detecting objects 10, the signal that detecting objects 10 back scattering is returned is collected through optical transmitting and receiving device 9, then through the B end of circulator 8 and C end after elder generation, transfers to beam splitter 12;

The output terminal of serial adjustable pad 11 is connected with the B port of beam splitter 12, the signal that local oscillator light and back scattering are returned mixes rear access balanced detector 13 by beam splitter 12, the output terminal of balanced detector 13 is connected with the input end of A/D capture card 14, the output terminal of A/D capture card 14 is connected with the input end of DSP data handling system 15, and the output terminal of DSP data handling system 15 is connected with computing machine 16.

Further, if described detecting objects 10 is atmospheric aerosol, then this laser radar is used for atmospheric sounding wind speed.

Further, described EOM2 is for generation of side frequency, and it comprises: amplitude modulaor, phase-modulator and frequency modulator.

Further, described first wave filter 4 comprises: Fiber Bragg Grating FBG, Fabry-Perot interferometer, M-Z interferometer, atom and molecule absorption chamber, Sagnac ring and multilayer dielectric film interference filter.

Further, described signal generator 3 is for providing the modulation signal of EOM2, and the frequency modulating signal that wherein signal generator 3 exports determines the size of double frequency spacing.

As seen from the above technical solution provided by the invention, it not only can measure the translational speed of hard goal, and can measure air wind speed.The method that the present invention is modulated by continuous light produces double-frequency laser, Doppler shift information is extracted by the mode of microwave, by DSP data processing, achieve detection of a target speed to show in real time, dual frequency sounder mode reduces the speckle noise that detection of a target out-of-flatness and atmospheric turbulence cause, and has the advantages such as detection accuracy is high, electromagnetism interference, compact conformation.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme of the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawings can also be obtained according to these accompanying drawings.

The structural representation of a kind of double frequency coherent wind laser radar based on single-frequency continuous light EOM modulation that Fig. 1 provides for the embodiment of the present invention;

The schematic diagram of the dual laser that Fig. 2 provides for the embodiment of the present invention.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on embodiments of the invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to protection scope of the present invention.

A kind of double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM that the embodiment of the present invention provides.As shown in Figure 1, it mainly comprises:

Continuous light laser instrument 1, electrooptic modulator (EOM) 2, signal generator 3, first wave filter 4, laser amplifier 5, second wave filter 6, beam splitter 7, circulator 8, optical transmitting and receiving device 9, serial adjustable pad 11,3dB beam splitter 12, balanced detector 13, A/D capture card 14, DSP data handling system 15 and computing machine 16, the annexation of each device is as follows:

The output terminal of continuous light laser instrument 1 is connected with the input end of EOM2, EOM2 output terminal is connected with the input end of the first wave filter 4, (the control signal input end of 3 is connected with the control signal output terminal of EOM2 signal generator, the output terminal of the first wave filter 4 is connected with the input end of laser amplifier 5, the output terminal of laser amplifier 5 is connected with the input end of the second wave filter 6, and the output terminal of the second wave filter 6 is connected with the input end of beam splitter 7;

Described beam splitter 7 is for being divided into two points by double-frequency laser, and wherein output terminals A exports as flashlight, and what output terminal B exported is local oscillator light; The output terminals A of beam splitter 7 is connected with the A port of circulator 8, and the output terminal B of beam splitter 7 is connected with the input end of serial adjustable pad 11,

The C end of circulator 8 is connected with the A port of beam splitter 12; The B port of circulator 8 is connected with optical transmitting and receiving device 9, the light beam irradiation of optical transmitting and receiving device 9 outgoing is on detecting objects 10, the signal that detecting objects 10 back scattering is returned is collected through optical transmitting and receiving device 9, then through the B end of circulator 8 and C end after elder generation, transfers to beam splitter 12;

The output terminal of serial adjustable pad 11 is connected with the B port of beam splitter 12, the signal that local oscillator light and back scattering are returned mixes rear access balanced detector 13 by beam splitter 12, the output terminal of balanced detector 13 is connected with the input end of A/D capture card 14, the output terminal of A/D capture card 14 is connected with the input end of DSP data handling system 15, and the output terminal of DSP data handling system 15 is connected with computing machine 16.

In the embodiment of the present invention, described continuous light laser instrument 1 is for outputting dual wavelength laser.

In the embodiment of the present invention, if described detecting objects 10 is atmospheric aerosol, then this laser radar is used for atmospheric sounding wind speed.

In the embodiment of the present invention, described signal generator 3 is for providing the modulation signal of EOM2, and the frequency modulating signal that wherein signal generator 3 exports determines the size of double frequency spacing.

The ASE noise that described second wave filter 6 produces for filtering laser amplifier 5.

Described optical transmitting and receiving device 9 can be focus adjustable telescope, can be realized the wind speed detection at different distance place by focusing.

In the embodiment of the present invention, described EOM2 is for generation of side frequency, and it includes but not limited to: amplitude modulaor, phase-modulator and frequency modulator.

In the embodiment of the present invention, described first wave filter 4 includes but not limited to: Fiber Bragg Grating FBG, Fabry-Perot interferometer, M-Z interferometer, atom and molecule absorption chamber, Sagnac ring and multilayer dielectric film interference filter.

Described first wave filter 4 is for filtering laser center frequency f _c, shown in Figure 2, f _cfor the centre frequency of laser, f _mfor modulating frequency, f ₁with f ₂for the side frequency that modulation obtains, f ₁with f _cdistance geometry f ₂with f _cdistance equal be f _m; First wave filter 4 filtering laser center frequency f _c, and leach side frequency f ₁with f ₂, thus creating the double-frequency laser for wind speed detection, the spacing of double-frequency laser is 2f _m.

For the ease of understanding the present invention, introduce the principle of the double frequency coherent wind laser radar based on continuous light modulation below.

The present invention is modulated by single-frequency continuous light EOM and produces bifrequency laser, next will first introduce the generation of double frequency, then sets forth the principle that double frequency coherent laser radar surveys wind.

Assuming that modulation signal is the cosine function of a time, namely

a(t)＝A _mcos(f _mt)(1)

In formula, A _mfor the amplitude of modulation signal, f _mfor the angular frequency of modulation signal.Laser modulation method can be divided into amplitude modulation, frequency modulation and intensity modulated by the character of modulation.The electric field of laser can be expressed as

E _c(t)＝A _ccos[f _c·t+φ _c(t)](2)

In formula, A _cfor amplitude, f _cfor angular frequency, φ _ct () is phasing degree.When carrying out Modulation and Amplitude Modulation, A _cbe no longer constant, its electric field becomes

E(t)＝A _c[1+m _acos(f _m·t+φ _m)]cos[f _c·t+φ _c(t)](3)

In formula, m _a=A _m/ A _cbe called amplitude modulation coefficient.

Utilize trigonometric function formula formula (3) to be launched, namely obtain the frequency spectrum formula of modulated wave, namely

$\begin{array}{c}E\left(t\right)=A_c\cos [f_c\·t+{\mathrm{\φ}}_c\left(t\right)]+\frac{m_a}{2}{A}_c\cos [(f_c+f_m)\·t+{\mathrm{\φ}}_c]\\ +\frac{m_a}{2}{A}_c\cos [(f_c-f_m)\·t+{\mathrm{\φ}}_c]\end{array}$

For frequency modulation (PFM), the f in formula (1) _cno longer constant, namely

f(t)＝f _c+k _fa(t)(5)

In formula, k _ffor scale-up factor.Then total phase place is

$\mathrm{\φ}\left(t\right)=\underset{0}{\overset{t}{\∫}}f\left(t\right)dt+{\mathrm{\φ}}_c=\underset{0}{\overset{t}{\∫}}\[f_c+k_{f}a\left(t\right)\]dt+{\mathrm{\φ}}_c=f_{c}t+\underset{0}{\overset{t}{\∫}}{k}_{f}a\left(t\right)dt+{\mathrm{\φ}}_c---\left(6\right)$

Formula (6) is updated in formula (1), and makes k _fa _m=f _fm, f _fm/ f _m=m _f, then the expression formula obtaining modulating wave is

E(t)＝A _ccos[f _c·t+m _fsin(f _mt)+φ _c(t)](7)

And for phase-modulation, the φ in formula (1) _cchanging Pattern along with modulation signal is changed.Therefore, frequency modulation and phase modulation are in fact all the total phasing degree of modulation, therefore, next only derive to frequency modulation.

Utilize triangle formula expansion (7),

E(t)＝A _c[cos(f _c·t+φ _c)cos(msin(f _mt))-sin(f _c·t+φ _c)sin(msin(f _mt))](8)

This angle modulation vibration is the periodic function of time, therefore can be analyzed to Fourier series, by the cos (msin (f in formula _m) and sin (msin (f t) _mt)) two expand into

$cos\left(msin\right(f_{m}t\left)\right)=J_0\left(m\right)+2\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}{J}_{2n}\left(m\right)cos\left(2{\mathrm{nf}}_{m}t\right)---(9-1)$

$sin\left(msin\right(f_{m}t\left)\right)=2\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}{J}_{2n-1}\left(m\right)cos\[(2n-1)f_{m}t)\]---(9-2)$

In formula, J _nm () is n rank first kind Bezier (Bessel) function of m, utilize this two relational expressions, just formula (8) can be expanded into

$\begin{array}{c}E\left(t\right)=A_c\{J_0\left(m\right)\cos (f_{c}t+{\mathrm{\φ}}_c)+J_1\left(m\right)\cos \[(f_c+f_m)t+{\mathrm{\φ}}_c\]\\ -J_1\left(m\right)\cos \[(f_c-f_m)t+{\mathrm{\φ}}_c\]+J_2\left(m\right)\cos \[(f_c+2f_m)t+{\mathrm{\φ}}_c\]\\ +J_2\left(m\right)\cos \[(f_c-2f_m)t+{\mathrm{\φ}}_c\]+\mathrm{...}\}\end{array}---\left(10\right)$

From formula (10), when single frequency sinusoidal ripple is modulated, the frequency spectrum of its angle modulated wave is made up of light carrier frequency and the infinite multipair side frequency symmetrical on its both sides.Frequency interval between each side frequency is f _m, the size J again of each side frequency amplitude ₀m () Bessel's function determines.From tabling look-up, as m=1, J ₀(m)=0.77, J ₁(m)=0.44, J ₂(m)=0.11, J ₃(m)=0.02....

When angular modulation coefficient is less (during m<<1), from Bessel function, the side frequency corresponding to high-order Bessel function of n >=2 can be ignored, so the frequency spectrum of angle modulated wave and the frequency spectrum of modulated wave have identical form.Therefore, angular modulation and Modulation and Amplitude Modulation all can modulate the side frequency shown in Fig. 2.

The electric field of the dual-wavelength laser of laser emitting can be expressed as

E(t)＝E ₁(t)+E ₂(t)＝A ₁expj[2πf ₁t+φ ₁(t)]+A ₂expj[2πf ₂t+φ ₂(t)](11)

In formula, A _iand φ _ibe amplitude and the phase place of i-th laser frequency.

When laser is radiated at the detection of a target 10, the electric field that back scattering is returned can be expressed as

E ₁₂(t)＝B ₁expj[2πf ₁₂t-2πf ₁τ+φ ₁(t-τ)+φ _1，speckle(t-τ)](12)

E ₂₂(t)＝B ₂expj[2πf ₂₂t-2πf ₂τ+φ ₂(t-τ)+φ _2，speckle(t-τ)](13)

In formula, B _i=A _i/ α, α are the total losses due to reflected light, f ₁₂=f ₁+ Δ f ₁, f ₂₂=f ₂+ Δ f ₂, Δ f ₁with Δ f ₂for the frequency change caused by the speed V at the detection of a target 9 place, i.e. Δ f ₁=2Vf ₁/ c, Δ f ₂=2Vf ₂wherein, c is the light velocity to/c, and τ is the time delay between local oscillator light and flashlight, φ _{1, speckle}(t-τ) and φ _{2, speckle}(t-τ) represents speckle noise respectively.The surface irregularity of the detection of a target, atmospheric turbulence and atmospheric aerosol and molecular velocity random motion all can cause speckle noise.When the detection of a target is hard goal, the phase perturbation that detection target surface out-of-flatness causes is

${\mathrm{\&phi;}}_{1,speckle}\left(t\right)=\&Integral;\frac{2\mathrm{\&pi;}\&times;2\mathrm{\&gamma;}(p,t)f_1}{c}dS---\left(14\right)$

${\mathrm{\&phi;}}_{1,speckle}\left(t\right)=\&Integral;\frac{2\mathrm{\&pi;}\&times;2\mathrm{\&gamma;}(p,t)f_2}{c}dS---\left(15\right)$

In formula, γ (p, t) represents the out-of-flatness of detection target surface, and S is the size of LASER SPECKLE.

But flashlight and local oscillator light are when the surperficial mixing of detector 13 detects, and due to detector only responsive bandwidth range signals, then the light field irradiance at detector place is

I ₁(t)＝2C ₁cos[2πΔf ₁t-2πf ₁τ+φ ₁(t-τ)-φ ₁(t)+φ _1，speckle(t-τ)](16)

I ₂(t)＝2C ₂cos[2πΔf ₂t-2πf ₂τ+φ ₂(t-τ)-φ ₂(t)+φ _2，speckle(t-τ)](17)

In formula, for the responsiveness of detector.

I ₁(t) and I ₂t () is gathered by A/D capture card after being detected by detector 13.Signal after collection carries out Frequency mixing processing again through DSP, namely calculates [I by DSP ₁(t)+I ₂(t)] ², process is launched to this formula, comprising Doppler shift item is

$\begin{array}{c}{I}_m\left(t\right)4C_1{C}_2\cos \&lsqb;2\mathrm{\&pi;}({\mathrm{\&Delta;f}}_1-{\mathrm{\&Delta;f}}_2)t-2\mathrm{\&pi;}\mathrm{\&Delta;}f\mathrm{\&tau;}+{\mathrm{\&phi;}}_1(t-\mathrm{\&tau;})\\ -{\mathrm{\&phi;}}_1\left(t\right)+{\mathrm{\&phi;}}_2(t-\mathrm{\&tau;})-{\mathrm{\&phi;}}_2\left(t\right)+{\mathrm{\&phi;}}_{1,speckle}(t-\mathrm{\&tau;})-{\mathrm{\&phi;}}_{2,speckle}(t-\mathrm{\&tau;})\&rsqb;\end{array}---\left(18\right)$

${\mathrm{\&phi;}}_{1,speckle}(t-\mathrm{\&tau;})-{\mathrm{\&phi;}}_{2,speckle}(t-\mathrm{\&tau;})=\&Integral;\frac{2f_m\&times;2\mathrm{\&pi;}\&times;2\mathrm{\&gamma;}(p,t)}{c}dS---\left(19\right)$

Formula (19) contains the velocity information V of the detection of a target, then

Δf ₁-Δf ₂＝4Vf _m/c(20)

Comparison expression (19) and formula (14) can be found out, compare and single-frequency coherent wind laser radar, optical frequency is converted to microwave signal by bifrequency laser radar, thus reduces the impact of the speckle noise that detector surface out-of-flatness causes.

By [the I that DSP calculates ₁(t)+I ₂(t)] ²item carries out Fourier transform and can obtain speed V information.As can be seen from formula (20), when detection of a target speed V mono-timing, f _mlarger, double-frequency difference DELTA f ₁-Δ f ₂larger.Therefore, can by the f regulated _mto adapt to varying environment requirement.In the present invention, by the trigger pip of conditioning signal occurring source, can reach and regulate double frequency spacing f _mobject.

The method that the embodiment of the present invention adopts EOM to modulate single-frequency continuous wave produces two side frequencys, wave filter filtering laser center frequency is utilized to produce dual-wavelength laser with the method leaching two side frequencys, the production method of this double frequency improves the stability of double frequency spacing, and double frequency spacing controls flexibly by regulating the trigger pip of modulator.

A kind of double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM that the embodiment of the present invention provides mainly has following beneficial effect:

1) the present invention adopts dual-wavelength laser as light source, by relevant beat frequency to detect the difference of dual wavelength Doppler shift with inversion speed, this detection method adopts microwave signal to extract Doppler shift information, reduces the speckle noise that detection of a target out-of-flatness and atmospheric turbulence cause.

2) the present invention adopts the method for modulation single-frequency continuous wave to produce two side frequencys, wave filter filtering baseband frequency is utilized to produce dual-wavelength laser with the method leaching two side frequencys, the production method of this double-frequency laser improves the stability of double frequency spacing, and double frequency spacing controls flexibly by regulating the trigger pip of modulator.

3) the present invention extracts Doppler shift information by microwave signal, has the feature of electromagnetism interference.Such as when frequency difference is 40GHz, then the frequency difference that the wind speed of 30m/s causes is 8000Hz.And traditional coherent laser radar adopts intermediate-freuqncy signal detection wind speed, intermediate-freuqncy signal is generally between 30MHz to 300MHz, and the wave band that this is just broadcasting station, Wireless Telecom Equipment uses, this band coverage is wide, it is intensive to use.Therefore, on the one hand, the use of intermediate-freuqncy signal, makes traditional coherent laser radar easily by the interference of electromagnetic environment; On the other hand, the electromagnetic signal of laser radar radiation when normal work will cause interference to other electronic equipment.

4) the present invention adopts DSP to carry out data processing, can realize realization process and the display of speed.

The above; be only the present invention's preferably embodiment, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.

Claims (5)

1., based on the double frequency coherent wind laser radar that single-frequency continuous light EOM modulates, it is characterized in that, comprising:

Continuous light laser instrument (1), electrooptic modulator EOM (2), signal generator (3), the first wave filter (4), laser amplifier (5), the second wave filter (6), beam splitter (7), circulator (8), optical transmitting and receiving device (9), serial adjustable pad (11), beam splitter (12), balanced detector (13), A/D capture card (14), DSP data handling system (15) and computing machine (16), the annexation of each device is as follows:

The output terminal of continuous light laser instrument (1) is connected with the input end of EOM (2), EOM (2) output terminal is connected with the input end of the first wave filter (4), the control signal input end of signal generator (3) is connected with the control signal output terminal of EOM (2), the output terminal of the first wave filter (4) is connected with the input end of laser amplifier (5), the output terminal of laser amplifier (5) is connected with the input end of the second wave filter (6), and the output terminal of the second wave filter (6) is connected with the input end of beam splitter (7);

Described beam splitter (7) is for being divided into two points by double-frequency laser, and wherein output terminals A exports as flashlight, and what output terminal B exported is local oscillator light; The output terminals A of beam splitter (7) is connected with the A port of circulator (8), and the output terminal B of beam splitter (7) is connected with the input end of serial adjustable pad (11),

The C end of circulator (8) is connected with the A port of beam splitter (12); The B port of circulator (8) is connected with optical transmitting and receiving device (9), the light beam irradiation of optical transmitting and receiving device (9) outgoing is on detecting objects (10), the signal that detecting objects (10) back scattering is returned is collected through optical transmitting and receiving device (9), hold through the B end of circulator (8) and C after elder generation again, transfer to beam splitter (12);

The output terminal of serial adjustable pad (11) is connected with the B port of beam splitter (12), balanced detector (13) is accessed after the signal that local oscillator light and back scattering are returned is mixed by beam splitter (12), the output terminal of balanced detector (13) is connected with the input end of A/D capture card (14), the output terminal of A/D capture card (14) is connected with the input end of DSP data handling system (15), and the output terminal of DSP data handling system (15) is connected with computing machine (16).

2. the double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM according to claim 1, is characterized in that, if described detecting objects (10) is atmospheric aerosol, then this laser radar is used for atmospheric sounding wind speed.

3. the double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM according to claim 1, it is characterized in that, described EOM (2) is for generation of side frequency, and it comprises: amplitude modulaor, phase-modulator and frequency modulator.

4. the double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM according to claim 1, it is characterized in that, described first wave filter (4) comprising: Fiber Bragg Grating FBG, Fabry-Perot interferometer, M-Z interferometer, atom and molecule absorption chamber, Sagnac ring and multilayer dielectric film interference filter.

5. the double frequency coherent wind laser radar modulated based on single-frequency continuous light EOM according to claim 1, it is characterized in that, described signal generator (3) is for providing the EOM modulation signal of (2), and the frequency modulating signal that wherein signal generator (3) exports determines the size of double frequency spacing.