CN107064956A - A kind of ground Terahertz cloud detection radar system and its detection method - Google Patents
A kind of ground Terahertz cloud detection radar system and its detection method Download PDFInfo
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Abstract
A kind of ground Terahertz cloud detection radar system and its detection method, linear FM signal generation module produces the linear FM signal of adjustable pulse width, frequency synthesizer module produces transmitting pumping signal and receives pumping signal, terahertz sources module produces terahertz sources signal, Terahertz echo-signal is converted to intermediate-freuqncy signal by Terahertz receiving module, intermediate-freuqncy signal receiving processing module produces baseband signal, signal processing module carries out signal transacting to baseband signal, and host computer completes cloud observation data inversion according to the signal processing results of signal processing module and handled.The present invention uses linear frequency modulation working system and adjustable pulse width, higher range resolution ratio can be obtained, reduce the requirement to system emission power, ground can be met and closely arrive remote cloud observation, the radar reflectivity factor information differentiated compared with high cloud section is provided, and observation area cloud space-time thin clouds can be further obtained as grand microscopic information, it simultaneously can be used for the detection of the molecule such as haze in environment.
Description
Technical field
The present invention relates to weather radar active remote sensing technical field, more particularly to a kind of ground Terahertz cloud detection radar system
And its detection method.
Background technology
Cloud plays very important effect in ground vapour system, by influence the sun to the shortwave radiation and the earth of the earth to
The long wave of external radiation, the radiation budget balance of influence ground vapour system；Cloud is into Yun Zhiyu main carriers, affects the whole earth
Water Cycle；Cloud is also to influence the main source of current climate research and weather forecast uncertain factor.Cloud is main distant
Sense means are divided into passive remote sensing and active remote sensing, and wherein passive remote sensing means can obtain the Macroscopic physical feature of cloud, coverage
Greatly, vertical and horizontal resolution ratio is low, and the development of active remote sensing means is later, but also achieves greater advance, and has obtained extensive
Using.
During past more than 20 years, the need for determining research are played the part of in promotion and cloud by hardware technology level in terrestrial climate
Influence is asked, the development of millimeter wave (35GHz and 94GHz are the most typical) cloud observation radar, and these thunders are promoted energetically both at home and abroad
It is successful up to being observed in cloud, has obtained extremely wide application.Specifically, 3 millimeter wave cloud observation radars can
For long-term observation sexual intercourse evolutionary process, the grand microscopic information of cloud section and cloud Internal dynamics process, Neng Gouti can be obtained
For higher space time resolution ratio.Cloud observation radar development experience several stages, wherein U.S. ARM millimeter waves cloud radar are seen
Survey schedule flag and millimetre-wave radar and be used for meteorological cloud and observe；The 94GHz cloud observation radars that CloudSat satellites are carried are indicated
The beginning of global cloud observation；94GHz Doppler's clouds observation radar that the EarthCARE satellites planned in transmitting in 2018 are carried will
Indicate the beginning of global cloud dynamics observation.And have concerned countries in the world at present and developing Terahertz frequency range cloud observation thunder
Reach, be mainly used in solving current ice cloud remote sensing capabilities deficiency and explore application of the radar in terms of haze, this will indicate that
The important directions that Terahertz frequency range cloud radar will develop as cloud radar from now on.
1989, the Mead of Massachusetts, USA university discusses 215GHz radar systems, and quantitative observation stratocumulus
With the experiment of mist, zenith observing is apart from 97-1900m；Nineteen ninety, Mead et al. have developed the non-coherent radar systems of 225GHz again,
Snowfall observation is carried out；2010, German H.Essen et al. have developed all solid state cloud detection radars of 220GHz, will be used for snowfall and
The detection of cloud.China has also carried out the development of related frequency range cloud Principles of Radar model machine during " 12 ".However, being so far
Only, not using the patent of pulse compression working system, the practicality ground cirrus observation radar for receiving and dispatching separate mode.
The content of the invention
The present invention provides a kind of ground Terahertz cloud detection radar system and its detection method, using linear frequency modulation working system
And adjustable pulse width, higher range resolution ratio can be obtained, the requirement to system emission power is reduced, ground low coverage can be met
There is provided compared with high cloud section radar reflectivity factor information, and observation area cloud can be further obtained to the observation of remote cloud
Space-time thin clouds simultaneously can be used for the detection of the molecule such as haze in environment as grand microscopic information.
In order to achieve the above object, the present invention provides a kind of ground Terahertz cloud detection radar system, comprising：
Linear FM signal generation module, the linear FM signal for producing adjustable pulse width；
Frequency synthesizer module, it is electrically connected with linear FM signal generation module, for producing transmitting pumping signal, connecing
Receive pumping signal, secondary down coversion local oscillation signal and global clock signal；
Terahertz sources module, it is electrically connected with frequency synthesizer module, for being produced under the excitation of transmitting pumping signal
Raw terahertz sources signal；
Separate antenna module is received and dispatched, it is electrically connected with terahertz sources module, for launching terahertz signal and receiving too
Hertz echo-signal；
Terahertz receiving module, it is electrically connected with transmitting-receiving separate antenna module and frequency synthesizer module, for receiving too
Hertz echo-signal, intermediate-freuqncy signal is converted in the case where receiving the excitation of pumping signal by Terahertz echo-signal；
Intermediate-freuqncy signal receiving processing module, it is electrically connected with frequency synthesizer module Terahertz receiving module, for basis
Secondary down coversion local oscillation signal carries out secondary down coversion to the intermediate-freuqncy signal received, produces baseband signal；
Signal processing module, it is electrically connected with intermediate-freuqncy signal receiving processing module and terahertz sources module, for realizing
Collection to baseband signal, storage and processing, and control to modules in ground Terahertz cloud detection radar system and logical
News；
Host computer, it is electrically connected with signal processing module, for being completed according to the signal processing results of signal processing module
Cloud observation data inversion processing.
Described terahertz sources module is included：
Terahertz sources frequency multiplication link, it is electrically connected with frequency synthesizer module, for frequency synthesizer module to be provided
Transmitting pumping signal carry out 12 frequencys multiplication, obtain transmitting terahertz signal；
Coupler, it is electrically connected with terahertz sources frequency multiplication link, for adhering to emitter real-time frequency, power information,
Demarcate the transmission signal of radar；
Power amplifier module, it is electrically connected with coupler and transmitting-receiving separate antenna module, for terahertz sources frequency multiplication link
The transmitting terahertz signal of offer, which exported after power amplification, gives transmitting-receiving separate antenna module；
Internal calibration component, it is electrically connected with coupler and signal processing module, for measurand transmitter real-time frequency and work(
Rate information.
Described Terahertz receiving module is included：
Terahertz receives frequency multiplication link, and it is electrically connected with frequency synthesizer module, for frequency synthesizer module to be provided
Reception pumping signal carry out 6 frequencys multiplication, obtain local oscillation signal；
Amplify filtration module, it is electrically connected with Terahertz and receives frequency multiplication link, for being amplified filtering to local oscillation signal；
Harmonic mixer, it is electrically connected with amplification filtration module, transmitting-receiving separate antenna module and intermediate-freuqncy signal reception processing
Module, the local oscillator for the Terahertz echo-signal and Terahertz that are received from transmitting-receiving separate antenna module to be received to frequency multiplication link
Signal mixing generation intermediate-freuqncy signal.
Described transmitting-receiving separate antenna module is included：
Transmitting antenna, it is electrically connected with the power amplifier module in terahertz sources module, for launching terahertz signal；
Reception antenna, it is electrically connected with the harmonic mixer in Terahertz receiving module, for receiving Terahertz echo letter
Number.
The present invention also provides a kind of detection method of ground Terahertz cloud detection radar system, comprises the steps of：
Step S1, linear FM signal generation module produce the linear FM signal of adjustable pulse width；
Step S2, frequency synthesizer module produce K-band exciting signal source according to linear FM signal；
Described K-band exciting signal source is included：Launch pumping signal, receive pumping signal, secondary down coversion local oscillator letter
Number and global clock signal；
Step S3, terahertz sources module produce terahertz sources signal under the excitation of transmitting pumping signal, pass through hair
Penetrate antenna transmitting；
The Terahertz that step S4, Terahertz receiving module will be received in the case where receiving the excitation of pumping signal by reception antenna
Echo-signal is converted to intermediate-freuqncy signal；
Step S5, intermediate-freuqncy signal receiving processing module carry out secondary down coversion to intermediate-freuqncy signal, produce baseband signal；
Step S6, signal processing module carry out signal transacting to baseband signal；
Step S7, host computer complete cloud observation data inversion processing according to the signal processing results of signal processing module.
Described step S3 is specifically comprised the steps of：
Step S3.1, terahertz sources frequency multiplication link will launch pumping signal and carry out 12 frequencys multiplication, obtain transmitting Terahertz
Signal；
Step S3.2, power amplifier module, which will be launched after terahertz signal carries out power amplification, to be exported to transmitting antenna.
Described step S4 is specifically comprised the steps of：
Step S4.1, Terahertz, which receive frequency multiplication link, will receive pumping signal 6 frequencys multiplication of progress, obtain local oscillation signal；
Step S4.2, amplification filtration module are amplified filtering to local oscillation signal；
The Terahertz echo-signal that step S4.3, harmonic mixer are received by local oscillation signal and from reception antenna is mixed life
Into intermediate-freuqncy signal.
In described step S6, the method that signal processing module carries out signal transacting to baseband signal specifically includes following step
Suddenly：
Step S6.1, time domain accumulation is carried out to the IQ components in the baseband signal that receives；
Step S6.2, IQ components are merged after time domain complex signal carry out pulse compression to obtain distance-amplitude information；
Step S6.3, poor fortune is carried out to its corresponding mathematic expectaion of same range bin amplitude after process of pulse-compression
Calculate, eliminate the interference of zero-frequency noise signal caused by direct current signal；
Step S6.4, to going direct current signal to carry out windowing process to improve Out-of-band rejection；
Step S6.5, the data in same range gate are entered row distance dimension FFT；
Each column sequences of pulsed signals after step S6.6, dimension of adjusting the distance FFT seeks its mould square and is added to obtain respectively
To the power spectrum degrees of data of respective pulses signal；
Step S6.7, the power spectrum degrees of data to acquisition are averaging, and obtain echo signal power；
Orientation dimension data after step S6.8, dimension of adjusting the distance FFT carries out azimuth dimension FFT, extracts doppler spectral
Information.
In described step S7, host computer completes cloud observation data inversion according to the signal processing results of signal processing module
The method of processing is included：Different distance is calculated according to the echo signal power and meteorological radar equation and range information of acquisition
Radar reflectivity factor data；According to doppler spectral acquisition of information cloud particle movable information.
The operating frequency range of described ground Terahertz cloud detection radar system is 237.9GHz~238GHz, bandwidth of operation
It is 2 μ s~1ms to be more than 5W, pulse width for 2~100MHz, regulable center frequency, power output, pulse minimum step be 2 μ s,
Pulse recurrence frequency is 500Hz~15kHz.
The present invention uses linear frequency modulation working system and adjustable pulse width, can obtain higher range resolution ratio, reduction pair
The requirement of system emission power, can meet ground and closely arrive the observation of remote cloud there is provided compared with high cloud section radar reflection
Rate factor information, and observation area cloud space-time thin clouds can be further obtained as grand microscopic information, it simultaneously can be used for mist in environment
The detection of the molecules such as haze.
Brief description of the drawings
Fig. 1 is the structured flowchart for the ground Terahertz cloud detection radar system that the present invention is provided.
Fig. 2 is the method flow diagram that signal processing module carries out signal transacting to baseband signal.
Embodiment
Below according to Fig. 1~Fig. 2, presently preferred embodiments of the present invention is illustrated.
As shown in figure 1, the present invention provides a kind of ground Terahertz cloud detection radar system, comprising：
Linear FM signal generation module 1,, should to obtain compared with high cloud section resolution ratio for producing linear FM signal
The μ s of pulsewidth 2 of linear FM signal~1ms is adjustable；
Frequency synthesizer module 2, it is electrically connected with linear FM signal generation module 1, for producing K-band pumping signal
Source, the K-band exciting signal source is included：Launch pumping signal (bandwidth about 8.3MHz), receive pumping signal (with a width of
9.89375GHz point-frequency signal), secondary down coversion local oscillation signal (working frequency 500MHz) and global clock signal (work
Working frequency is 100MHz point-frequency signals)；
Terahertz sources module 3, it is electrically connected with frequency synthesizer module 2, under the excitation of transmitting pumping signal
Produce terahertz sources signal；
Separate antenna module 5 is received and dispatched, it is electrically connected with terahertz sources module 3, for launching terahertz signal and receiving
Terahertz echo-signal, while ensureing the isolation of transmitting-receiving；
Terahertz receiving module 4, it is electrically connected with transmitting-receiving separate antenna module 5 and frequency synthesizer module 2, for receiving
Terahertz echo-signal, intermediate-freuqncy signal is converted in the case where receiving the excitation of pumping signal by Terahertz echo-signal；
Intermediate-freuqncy signal receiving processing module 6, it is electrically connected with frequency synthesizer module 2 and Terahertz receiving module 4, is used for
Secondary down coversion is carried out to the intermediate-freuqncy signal received according to secondary down coversion local oscillation signal, baseband signal is produced；
Signal processing module 7, it is electrically connected with intermediate-freuqncy signal receiving processing module 6 and terahertz sources module 3, for reality
Collection existing to baseband signal, storage and processing, and control to modules in ground Terahertz cloud detection radar system and
Communication；
Host computer 8, it is electrically connected with signal processing module 7, and (in the present embodiment, host computer 8 passes through 422 communication interfaces or light
Fiber communication interface connects signal processing module 7), for completing cloud observation number according to the signal processing results of signal processing module 7
According to inversion procedure, the grand microcosmic visualization result of the clouds such as radar reflectivity factor, efficient radius of cloud particle, cloud water content is obtained.
As shown in figure 1, described terahertz sources module 3 is included：
Terahertz sources frequency multiplication link 301, it is electrically connected with frequency synthesizer module 2, for by frequency synthesizer module 2
The transmitting pumping signal of offer carries out 12 frequencys multiplication, obtains the transmitting terahertz signal that frequency is 237.9GHz~238GHz；This
In embodiment, the terahertz sources frequency multiplication link 301 uses triple-frequency harmonics frequency mixer, and power output is more than 15mW；
Coupler 302, it is electrically connected with terahertz sources frequency multiplication link 301, for adhering to emitter real-time frequency, power
Information, demarcates the transmission signal of radar；
Power amplifier module 303, it is electrically connected with coupler 302 and transmitting-receiving separate antenna module 5, for terahertz sources times
The transmitting terahertz signal that frequency link 301 is provided, which exported after power amplification, gives transmitting-receiving separate antenna module 5；The present embodiment
In, the power amplifier module 303 uses travelling-wave tubes vacuum tube amplifier, and the transmission power of final transmitting terahertz signal is more than 5W, work
Make 2~100MHz of bandwidth (center frequency point is adjustable, and bandwidth is adjustable), the μ s of pulse width 2~1ms is adjustable, pulse recurrence frequency 500Hz
~15kHz；
Internal calibration component 304, it is electrically connected with coupler 302 and signal processing module 7, for the real-time frequency of measurand transmitter
Rate and power information.
As shown in figure 1, described Terahertz receiving module 4 is included：
Terahertz receives frequency multiplication link 401, and it is electrically connected with frequency synthesizer module 2, for by frequency synthesizer module 2
The reception pumping signal of offer carries out 6 frequencys multiplication, and acquisition frequency is (defeated for 118.725GHz (regulable center frequency) local oscillation signal
Go out power about 5mW)；
Amplify filtration module 402, it is electrically connected with Terahertz and receives frequency multiplication link 401, for being put to local oscillation signal
Big filtering；
Harmonic mixer 403, it is electrically connected with amplification filtration module 402, transmitting-receiving separate antenna module 5 and intermediate-freuqncy signal and connect
Processing module 6 is received, for the Terahertz echo-signal and Terahertz that are received from transmitting-receiving separate antenna module 5 to be received into frequency multiplier chain
The local oscillation signal mixing generation intermediate-freuqncy signal (center frequency point is in 500MHz) on road 401.
As shown in figure 1, described transmitting-receiving separate antenna module 5 is included：
Transmitting antenna 501, it is electrically connected with the power amplifier module 303 in terahertz sources module 3, for launching Terahertz letter
Number；
Reception antenna 502, it is electrically connected with the harmonic mixer 403 in Terahertz receiving module 4, for receiving Terahertz
Echo-signal.
The present invention also provides a kind of detection method of ground Terahertz cloud detection radar, comprises the steps of：
Step S1, linear FM signal generation module produce the μ s of pulsewidth 2~adjustable linear FM signals of 1ms；
Step S2, frequency synthesizer module produce K-band exciting signal source according to linear FM signal；
Described K-band exciting signal source is included：Launch pumping signal, receive pumping signal, secondary down coversion local oscillator letter
Number and global clock signal；
Step S3, terahertz sources module produce terahertz sources signal under the excitation of transmitting pumping signal, pass through hair
Penetrate antenna transmitting；
The Terahertz that step S4, Terahertz receiving module will be received in the case where receiving the excitation of pumping signal by reception antenna
Echo-signal is converted to intermediate-freuqncy signal；
Step S5, intermediate-freuqncy signal receiving processing module carry out secondary down coversion to intermediate-freuqncy signal, produce baseband signal；
Step S6, signal processing module carry out signal transacting to baseband signal；
Step S7, host computer complete cloud observation data inversion processing according to the signal processing results of signal processing module.
Described step S3 is specifically comprised the steps of：
Step S3.1, terahertz sources frequency multiplication link will launch pumping signal and carry out 12 frequencys multiplication, obtain frequency and be
237.9GHz~238GHz transmitting terahertz signal；
Step S3.2, power amplifier module, which will be launched after terahertz signal carries out power amplification, to be exported to transmitting antenna；
The transmission power of final transmitting terahertz signal is more than 5W, and (center frequency point is adjustable, and bandwidth can by bandwidth of operation 100MHz
Adjust), the μ s of pulse width 2~1ms is adjustable, pulse recurrence frequency 500Hz~15kHz.
Described step S4 is specifically comprised the steps of：
Step S4.1, Terahertz, which receive frequency multiplication link, will receive pumping signal 6 frequencys multiplication of progress, obtain frequency and be
118.725GHz (regulable center frequency) local oscillation signal (power output about 5mW)；
Step S4.2, amplification filtration module are amplified filtering to local oscillation signal；
The Terahertz echo-signal that step S4.3, harmonic mixer are received by local oscillation signal and from reception antenna is mixed life
Into intermediate-freuqncy signal (center frequency point is in 500MHz).
As shown in Fig. 2 in described step S6, the method that signal processing module carries out signal transacting to baseband signal is specific
Comprise the steps of：
In step S6.1, the present embodiment, signal transacting is carried out to 1024 row pulse signal IQ components, 1204 row pulses are believed
Number resolves into 64 groups, and every group constitutes for 16 adjacent pulse signals；To every 16 phases in the baseband signal that receives
The IQ components of adjacent pulse signal carry out time domain accumulation (also referred to as coherent integration)；
The step is main to be used to lift signal to noise ratio in the case of echo signal to noise ratio is relatively low, so that meteorologic signal is revealed；
Step S6.2, IQ components are merged after time domain complex signal carry out pulse compression to obtain distance-amplitude information；
Wherein, radar horizon scope takes 1km~12km, a length of 50m of range bin；
Step S6.3, poor fortune is carried out to its corresponding mathematic expectaion of same range bin amplitude after process of pulse-compression
Calculate, to eliminate the interference of zero-frequency noise signal caused by direct current signal；
Step S6.4, to going direct current signal to carry out windowing process to improve Out-of-band rejection；It is specific to use window shape formula and add
Several layers of windows need to be adjusted according to actual conditions, tentatively can be using modes such as conventional hamming, Haining or rectangular windows；
Step S6.5, the data in same range gate are entered row distance dimension FFT；
Each column pulse data signal sequence after step S6.6, dimension of adjusting the distance FFT is sought its mould square and is added respectively
To obtain the power spectrum degrees of data of respective pulses signal；
Step S6.7,64 groups of power spectrum degrees of data to acquisition are averaging, the pulsating nature larger for reducing power spectrum,
Complete spectrum averaging step and obtain echo signal power simultaneously；
64 groups of data of azimuth dimension after step S6.8, dimension of adjusting the distance FFT carry out azimuth dimension FFT, how general extract
Strangle spectrum information.
In described step S7, host computer completes cloud observation data inversion according to the signal processing results of signal processing module
The method of processing is included：Different distance is calculated according to the echo signal power and meteorological radar equation and range information of acquisition
Radar reflectivity factor data；
According to doppler spectral acquisition of information cloud particle movable information.
It is relatively more for the atmospheric window of Terahertz frequency range, in view of current Terahertz frequency range hardware technological development and cloud are seen
The demand of survey, the ground Terahertz cloud detection radar system work provided in combination with the division of International Telecommunication Union's frequency range, the present invention
Working frequency scope is 237.9GHz~238GHz, and 2~100MHz of bandwidth of operation (adjustable), regulable center frequency, power output are big
In 5W, the μ s of pulse width 2~1ms (μ s of minimum step 2), pulse recurrence frequency be 500Hz~15kHz (minimum step 500Hz,
It is adjustable).
Existing hardware development level in view of Terahertz radar system and the demand for cloud observation, the present invention are selected
Chirp (or CW with frequency modulation) working system.The optimal cloud of mould observation requirementses is forecast for the subfield value for requiring higher
Section resolution ratio is 0.3km, in addition in view of information more fine inside further research cloud, this radar cloud section resolution ratio
Theoretical value 1.5m~300m (adjustable).Ice cloud is generally in the region away from ground level 7,8km and the above, is abundant study too
Hertz cloud detection radar considers to be placed in away from ground level about 2km to the detectivity of ice cloud, ground Terahertz cloud detection radar system
Region above is observed (now air is about 2dB in theory to the two-way attenuation of 237.9GHz~238GHz signals)；It is right
The position that height above sea level is 0m can be placed in the observation of haze or low latitude water cloud to be observed.In fact, the observation of ice cloud
Capability Requirement is higher than the observation to haze or low latitude water cloud, will carry out parameter designing introduction according to ice cloud observation requirementses below.
Specific radar operating distance is limited by transmission power, signal pulsewidth, antenna gain, atmospheric attenuation and cloud section resolution ratio etc.,
Radar system parameters can specifically be weighed according to the meteorological radar equation of formula (1).
Above formula parameter is defined as follows：
Rmax：The farthest operating distance of radar；
Pt：Radar transmitted pulse power；
G：Dual-mode antenna gain；
θ：Antenna azimuth；
Antenna elevation angle；
τ’：The compression afterpulse time corresponding to cloud section resolution ratio；
K：Decay factor of the electromagnetic wave in spatial；
Z：Radar reflectivity factor；
B：Signal transmitted bandwidth；
τ：Radar transmitted pulse width；
Smin：Radar Receiver Sensitivity；
λ：Radar carrier wavelength；
La：Round trip atmospheric attenuation；
Ls：System loss；
In this example, radar transmission power 5W, dual-mode antenna gain are all 60.5dBi, antenna azimuth and the angle of pitch
About 0.1 °, the quadratic power that effectively pulsewidth is about 0.33 μ s, K after pulse pressure be that 0.93, reflectivity factor Z is sent out for -40dBZ, signal
It is that 1ms, system sensitivity are that -124dBW, wavelength are about 1.3mm, round trip atmospheric attenuation to penetrate with a width of 3MHz, fire pulse width
It is 6dB for 2dB and system loss, now calculates and obtain operating distance about 12km, it is contemplated that observation position is away from ground level
About 2km, cirrus height just occurs at away from ground 7,8km, so being to expire in this Terahertz cloud detection radar Systems Theory
Sufficient cirrus observation.
The present invention has advantages below：
1st, use normal pulsed working method more presently disclosed Terahertz cloud detection radar, one is obtained with narrower pulse
Determine resolution ratio, and to sacrifice power as cost, its optimal cloud section resolution ratio is only 15m.And the present invention uses linear frequency modulation arteries and veins
Compression scheme is rushed, higher range resolution ratio can be not only obtained, the requirement of system emission power can also be reduced.
2nd, normal pulsed working method is used presently disclosed Terahertz cloud detection radar, to obtain preferably distance point more
Its pulse width of resolution is adjustable in the range of the μ s of 100ns~3.And the present invention from distinct pulse widths be used for observe different zones (by
In can also use a kind of pulse width from transmitting-receiving separate type system), the Terahertz of this also compatible duplexer form
Cloud detection radar.
3rd, use normal pulsed working method more presently disclosed Terahertz cloud detection radar, not yet consider to utilize Doppler
The problem of testing the speed.The present invention uses linear frequency modulation working system, and adjustable pulse width (the μ s of scope 2~1ms), utilizes distance-how general
Observation cloud sector domain doppler information can be obtained by strangling two-dimensional digital signal processing mode, can be used for obtaining radar using doppler information
Particle rapidity information in the cloud of sensing, available for research cloud dynamics process.
Although present disclosure is discussed in detail by above preferred embodiment, but it should be appreciated that above-mentioned
Description is not considered as limitation of the present invention.After those skilled in the art have read the above, for the present invention's
A variety of modifications and substitutions all will be apparent.Therefore, protection scope of the present invention should be limited to the appended claims.
Claims (10)
1. a kind of ground Terahertz cloud detection radar system, it is characterised in that include：
Linear FM signal generation module（1）, the linear FM signal for producing adjustable pulse width；
Frequency synthesizer module（2）, it is electrically connected with linear FM signal generation module（1）, for produce transmitting pumping signal,
Receive pumping signal, secondary down coversion local oscillation signal and global clock signal；
Terahertz sources module（3）, it is electrically connected with frequency synthesizer module（2）, under the excitation of transmitting pumping signal
Produce terahertz sources signal；
Receive and dispatch separate antenna module（5）, it is electrically connected with terahertz sources module（3）, for launching terahertz signal and receiving
Terahertz echo-signal；
Terahertz receiving module（4）, it is electrically connected with transmitting-receiving separate antenna module（5）With frequency synthesizer module（2）, for connecing
Terahertz echo-signal is received, Terahertz echo-signal is converted into intermediate-freuqncy signal in the case where receiving the excitation of pumping signal；
Intermediate-freuqncy signal receiving processing module（6）, it is electrically connected with frequency synthesizer module（2）With Terahertz receiving module（4）, use
In carrying out secondary down coversion to the intermediate-freuqncy signal received according to secondary down coversion local oscillation signal, baseband signal is produced；
Signal processing module（7）, it is electrically connected with intermediate-freuqncy signal receiving processing module（6）With terahertz sources module（3）, it is used for
Realize collection, storage and the processing, and the control to modules in ground Terahertz cloud detection radar system to baseband signal
And communication；
Host computer（8）, it is electrically connected with signal processing module（7）, for according to signal processing module（7）Signal processing results
Complete cloud observation data inversion processing.
2. ground Terahertz cloud detection radar system as claimed in claim 1, it is characterised in that described terahertz sources module
（3）Comprising：
Terahertz sources frequency multiplication link（301）, it is electrically connected with frequency synthesizer module（2）, for by frequency synthesizer module
（2）The transmitting pumping signal of offer carries out 12 frequencys multiplication, obtains transmitting terahertz signal；
Coupler（302）, it is electrically connected with terahertz sources frequency multiplication link（301）, for monitoring emitter real-time frequency, power
Information, demarcates the transmission signal of radar；
Power amplifier module（303）, it is electrically connected with coupler（302）With transmitting-receiving separate antenna module（5）, for terahertz sources
Frequency multiplication link（301）The transmitting terahertz signal of offer, which exported after power amplification, gives transmitting-receiving separate antenna module（5）；
Internal calibration component（304）, it is electrically connected with coupler（302）And signal processing module（7）, it is real-time for measurand transmitter
Frequency and power information.
3. ground Terahertz cloud detection radar system as claimed in claim 2, it is characterised in that described Terahertz receiving module
（4）Comprising：
Terahertz receives frequency multiplication link（401）, it is electrically connected with frequency synthesizer module（2）, for by frequency synthesizer module
（2）The reception pumping signal of offer carries out 6 frequencys multiplication, obtains local oscillation signal；
Amplify filtration module（402）, it is electrically connected with Terahertz and receives frequency multiplication link（401）, for being put to local oscillation signal
Big filtering；
Harmonic mixer（403）, it is electrically connected with amplification filtration module（402）, transmitting-receiving separate antenna module（5）And intermediate-freuqncy signal
Receiving processing module（6）, for will from transmitting-receiving separate antenna module（5）The Terahertz echo-signal and Terahertz received is received
Frequency multiplication link（401）Local oscillation signal mixing generation intermediate-freuqncy signal.
4. ground Terahertz cloud detection radar system as claimed in claim 3, it is characterised in that described transmitting-receiving separate antenna mould
Block（5）Comprising：
Transmitting antenna（501）, it is electrically connected with terahertz sources module（3）In power amplifier module（303）, for launching Terahertz
Signal；
Reception antenna（502）, it is electrically connected with Terahertz receiving module（4）In harmonic mixer（403）, for receiving terahertz
Hereby echo-signal.
5. a kind of detection method of the ground Terahertz cloud detection radar system in 1-4 such as claim as described in any one, it is special
Levy and be, comprise the steps of：
Step S1, linear FM signal generation module produce the linear FM signal of adjustable pulse width；
Step S2, frequency synthesizer module produce K-band exciting signal source according to linear FM signal；
Described K-band exciting signal source is included：Launch pumping signal, receive pumping signal, secondary down coversion local oscillation signal and
Global clock signal；
Step S3, terahertz sources module produce terahertz sources signal under the excitation of transmitting pumping signal, by launching day
Line is launched；
The Terahertz echo that step S4, Terahertz receiving module will be received in the case where receiving the excitation of pumping signal by reception antenna
Signal is converted to intermediate-freuqncy signal；
Step S5, intermediate-freuqncy signal receiving processing module carry out secondary down coversion to intermediate-freuqncy signal, produce baseband signal；
Step S6, signal processing module carry out signal transacting to baseband signal；
Step S7, host computer complete cloud observation data inversion processing according to the signal processing results of signal processing module.
6. the detection method of ground Terahertz cloud detection radar system as claimed in claim 5, it is characterised in that described step
S3 is specifically comprised the steps of：
Step S3.1, terahertz sources frequency multiplication link will launch pumping signal and carry out 12 frequencys multiplication, obtain transmitting terahertz signal；
Step S3.2, power amplifier module, which will be launched after terahertz signal carries out power amplification, to be exported to transmitting antenna.
7. the detection method of ground Terahertz cloud detection radar system as claimed in claim 6, it is characterised in that described step
S4 is specifically comprised the steps of：
Step S4.1, Terahertz, which receive frequency multiplication link, will receive pumping signal 6 frequencys multiplication of progress, obtain local oscillation signal；
Step S4.2, amplification filtration module are amplified filtering to local oscillation signal；
In the Terahertz echo-signal mixing generation that step S4.3, harmonic mixer are received by local oscillation signal and from reception antenna
Frequency signal.
8. the detection method of ground Terahertz cloud detection radar system as claimed in claim 7, it is characterised in that described step
In S6, the method that signal processing module carries out signal transacting to baseband signal is specifically comprised the steps of：
Step S6.1, time domain accumulation is carried out to the IQ components in the baseband signal that receives；
Step S6.2, IQ components are merged after time domain complex signal carry out pulse compression to obtain distance-amplitude information；
Step S6.3, difference operation is carried out to its corresponding mathematic expectaion of same range bin amplitude after process of pulse-compression, disappeared
Except the interference of zero-frequency noise signal caused by direct current signal；
Step S6.4, to going direct current signal to carry out windowing process to improve Out-of-band rejection；
Step S6.5, the data in same range gate are entered row distance dimension FFT；
Each column sequences of pulsed signals after step S6.6, dimension of adjusting the distance FFT seeks its mould square and is added to obtain pair respectively
Answer the power spectrum degrees of data of pulse signal；
Step S6.7, the power spectrum degrees of data to acquisition are averaging, and obtain echo signal power；
Orientation dimension data after step S6.8, dimension of adjusting the distance FFT carries out azimuth dimension FFT, extracts doppler spectral information.
9. the detection method of ground Terahertz cloud detection radar system as claimed in claim 8, it is characterised in that described step
In S7, the method that host computer completes cloud observation data inversion processing according to the signal processing results of signal processing module is included：Root
The radar reflectivity factor of different distance is calculated according to the echo signal power and meteorological radar equation and range information of acquisition
Data；According to doppler spectral acquisition of information cloud particle movable information.
10. the detection method of ground Terahertz cloud detection radar system as claimed in claim 9, it is characterised in that described ground
The operating frequency range of base Terahertz cloud detection radar system is 237.9GHz ~ 238GHz, and bandwidth of operation is 2 ~ 100MHz, center frequency
Rate is adjustable, to be more than 5W, pulse width be 2 μ s ~ 1ms to power output, and pulse minimum step is that 2 μ s, pulse recurrence frequency are 500Hz
~15kHz。
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