CN104569980B - Ground terahertz radar system for detecting cloud - Google Patents
Ground terahertz radar system for detecting cloud Download PDFInfo
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- CN104569980B CN104569980B CN201510040930.4A CN201510040930A CN104569980B CN 104569980 B CN104569980 B CN 104569980B CN 201510040930 A CN201510040930 A CN 201510040930A CN 104569980 B CN104569980 B CN 104569980B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/95—Radar or analogous systems specially adapted for specific applications for meteorological use
- G01S13/951—Radar or analogous systems specially adapted for specific applications for meteorological use ground based
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
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Abstract
The invention discloses a ground terahertz radar system for detecting a cloud. The system comprises a terahertz transmitting module, a terahertz receiving module, a terahertz transmitting-and-receiving antenna module, a terahertz signal processing module and an upper computer module; the center frequency of a terahertz signal transmitted by the terahertz transmitting module is 220 GHz, the work bandwidth is 5 GHz, the transmitting power is 200 mW, the pulse width is adjustable ranging from 100ns to 3mus and the adjusted step length is 100ns, and the pulse repletion frequency is adjustable ranging from 1KHz to 10KHz and the adjusted step length is 1KHz. Compared with a laser radar and a millimeter wave radar, the ground terahertz radar system for detecting the cloud utilizes a set of parameters applicable to the cloud detection and is capable of penetrating into a thin cloud and an extremely thin cloud to carry out the three-dimensional structure detection for the cloud, and therefore not only a macrostructure such as the cloud thickness, the cloud height, the number of cloud layers, the vertical section variance of the cloud can be obtained, but also a microstructure such as the size, the shape, and the ice water content of a cloud particle can be obtained.
Description
Technical field
The present invention relates to Radar Technology field, more particularly to a kind of ground Terahertz radar system for surveying cloud.
Background technology
Cloud be it is most important in global climate model be also one of most doubt meteorological element, it is flat to earth energy
Weighing apparatus, climate change and weather modification have important function.Cloud is by affecting solar shortwave radiation and earth long-wave radiation, control
Earth energy budget.The monitoring of the distribution character and its evolution motor process of cloud is for research Global climate change, weather forecast
Deng with very important effect.
Research at present is surveyed the means of cloud and is mainly microwave radar, specifically includes microwave radiometer, machine and throws sonde and milli
Metric wave cloud detection radar etc..Wherein, microwave radiometer and machine are thrown sonde and can obtain certain cloud information, but can not penetrate spissatus
Top layer detect its vertical dimension and internal structure, the microcosmic such as size and shape, the ice water content of cloud particle can not be obtained
Characteristic.
Sonde is thrown compared to microwave radiometer and machine, millimetre-wave radar has more high detection sensitivity, tool to cloud particle
There is the ability for penetrating cloud, therefore not only can macroscopically describe the cloud external structures such as cloud thickness, the cloud level, cloud layer can also be described
The cloud internal physical structure of number, vertical section change etc.；And, the millimeter wave that millimetre-wave radar sends is closer to cloud particle
Yardstick, it utilize scattering propertiess of the cloud particle to electromagnetic wave, the microscopic characteristics of cloud are analyzed by cloud radar return, including
The information such as the size of cloud particle, shape, ice water content.First millimeter wave that NASA in 2004 succeeds in sending up surveys cloud thunder
Up to satellite --- CloudSat, the Main Load of the satellite are exactly the cloud section radar (cloud that a service band is 94GHz
Profiling radar, abbreviation CPR), for realizing the measurement of cloud layer internal information.But, millimetre-wave radar is for spissatus spy
Survey relatively effectively, too strong to the less cloud particle penetrance of particle diameter due to which, echo strength is weaker, therefore to thin cloud Effect on Detecting
It is not good, or even cannot detect.
Another means of research cloud are laser radars, and for example CALIPSO laser radars provide a large amount of tropopause
Thin ice cloud information.But laser penetration power is weaker, cloud layer surface can be only measured, cloud internal information cannot be obtained.
But, existing cloud measurement means also have some limitations：
(1) microwave radar is too strong to the less cloud particle penetrance of particle diameter, and echo strength is weaker, to thin cloud and very thin cloud very
Cannot extremely detect；
(2) laser radar penetration power is weaker, can only measure cloud layer surface, therefore is merely capable of providing cloud layer surface letter
Breath, it is impossible to stretch into the three-dimensional detection that cloud structure is done inside cloud；
(3) for very thin cloud and Cloudless atmosphere micropartical change, such as cloud particle size and shape, cloud particle, frozen water contains
Amount carries out high-precision detection and inverting, needs wavelength closer to the detection system of micropartical yardstick, and provides higher resolution
And sensitivity.
As millimeter wave cloud detection radar etc. surveys the application of cloud means, next atmospheric window frequency range becomes inevitable for surveying cloud
Trend.In recent years, with the continuous development of THz source technology, THz wave (0.1THz～10THz) should in meteorological detection etc.
There is with potential and important science and using value, cause the interest of related scholar, become new research direction.
The content of the invention
In view of this, the invention provides a kind of ground Terahertz radar system for surveying cloud, which realizes thin cloud and pole
Thin cloud internal structure external structure detection, and higher resolution and sensitivity can be provided.
In order to solve above-mentioned technical problem, what the present invention was realized in：
A kind of ground Terahertz radar system for surveying cloud, including：Terahertz sources module, Terahertz receiver module,
Terahertz dual-mode antenna module, terahertz signal processing module and upper computer module；
Terahertz sources module, the intermediate-freuqncy signal source for being produced using Terahertz receiver module complete terahertz signal
Produce and power amplification, then launched by Terahertz dual-mode antenna module；The center of the terahertz signal launched
Frequency is 220GHz, and bandwidth of operation is 5GHz, and transmission power is 200mW, pulse width be it is adjustable in the range of the μ s of 100ns～3 and
Regulation step-length is 100ns, and pulse recurrence frequency is adjustable in the range of 1KHz～10KHz and regulation step-length is 1KHz；
Terahertz receiver module, for completing the generation of derived reference signal, the generation of intermediate-freuqncy signal source, receiving and dispatching to Terahertz
The down coversion and secondary IF process of the Terahertz echo-signal that Anneta module is received, is then sent to terahertz signal and processes mould
Block；The mid frequency of the Terahertz receiver module is 220GHz, and bandwidth of operation is 5GHz, and receiving sensitivity is better than -80dBm, dynamic
State scope is better than 60dB；
Terahertz signal processing module, for realizing collection, storage and the process of the secondary intermediate-freuqncy signal of Terahertz echo；
Upper computer module is communicated with terahertz signal processing module and Terahertz receiver module respectively, to realize data
Transmission and the comprehensive control of frequency.
Preferably, the system further includes Terahertz internal calibration module, and the Terahertz internal calibration module is sent out from Terahertz
The terahertz signal that transmitting is obtained in module is penetrated, and which is carried out and Terahertz receiver module identical down-converted, then
Being sent to Terahertz receiver module carries out secondary IF process, and the secondary intermediate-freuqncy signal of internal calibration of acquisition is sent to terahertz signal
Processing module；Terahertz signal processing module further checks sending out for terahertz sources signal according to the secondary intermediate-freuqncy signal of internal calibration
Penetrate power and whether frequency offsets, the amplifying power of terahertz sources module is adjusted according to transmission power deviant, according to frequency
The generation of the intermediate-freuqncy signal source of skew adjustment Terahertz receiver module.
Preferably, the terahertz sources module includes Terahertz frequency multiplication link, Terahertz power amplifier and bonder；
The Terahertz frequency multiplication link, for the intermediate-freuqncy signal source frequency multiplication that Terahertz receiver module is produced is obtained Terahertz
The signal of frequency range；Frequency multiplication is realized using the cascade system of two+two frequencys multiplication of frequency multiplication+frequency tripling：Terahertz receiver module is received first
The signal that the frequency of offer is 18.33GHz ± 0.208GHz, power is 0dBm, by the E ripples of two varactor doublers composition
Section quadrupler and E band filter obtain the output of 73.2GHz ± 0.832GHz, then synthesize through E band powers
Device obtains the output that 73.2GHz ± 0.832GHz, power are 300mW, finally drives 220GHz frequency triplers, by frequency tripler most
220GHz ± 2.5GHz is realized eventually, and power is the transmission signal of 10mW, is transmitted to Terahertz power amplifier；
Wherein, E wave bands quadrupler is made up of two varactor doublers, is Ka varactor doublers and E wave band varactor doublers respectively,
The signal frequency multiplication of 18.33GHz ± 0.208GHz is that frequency is 36.666GHz ± 1GHz signals by Ka varactor doublers, then by E wave bands
Signal of the varactor doubler frequency multiplication for 73.333GHz ± 0.832GHz；
Terahertz power amplifier, for the terahertz signal that Terahertz frequency multiplication link is exported is carried out power amplification；
Bonder, for the signal output that produces Terahertz power amplifier to Terahertz dual-mode antenna module and terahertz
Hereby internal calibration module.
Preferably, the Terahertz receiver module includes that referrer module, secondary ifd module, local oscillator module and down coversion connect
Receive link module；
Referrer module, for producing reference frequency source for Terahertz receiver module, reference frequency source is 100MHz；
Local oscillator module, for being that Terahertz receiver module and terahertz sources module produce intermediate-freuqncy signal source；The local oscillator
Module by the Frequency Hopping Signal of 2.18GHz～3.203GHz is divided into after amplifier F0 and power splitter G1 are processed two-way, one
Road sequentially pass through wave filter L1, amplifier F1, frequency mixer H1, wave filter L2, amplifier F2 process after produce 1 road 17.83GHz～
18.853GHz signal output；After power splitter G1 process another road signal for producing sequentially pass through wave filter L3, amplifier F3,
Frequency mixer H2, wave filter L4, amplifier F4 process after Jing by power splitter G2 produce 2 road 17.74GHz～18.763GHz signal
Output；Wherein the signal output of 17.83GHz～18.853GHz gives terahertz sources module, used as in terahertz sources module
Frequency source signal；The signal output of 17.74GHz～18.763GHz is to down coversion receives link module and Terahertz internal calibration mould
Block, as down coversion receives link module and the intermediate-freuqncy signal source of Terahertz internal calibration module；
Down coversion receives link module, for the Terahertz thunder obtained to reception antenna in Terahertz dual-mode antenna module
Down coversion is carried out up to cloud echo signal is surveyed；
Secondary ifd module, exports for the 1080MHz by Terahertz receives link module or Terahertz internal calibration module
The 1020MHz signals produced with fixed local vibration source carry out mixing and obtain bis- intermediate-freuqncy signals of 60MHz, export at terahertz signal
Reason module.
Preferably, the down coversion receives link module, the letter of the 17.74GHz～18.763GHz produced from local oscillation signal
Number output extract the signal of 18.04GHz～18.45GHz through frequency tripler, wave filter L5, amplifier F5, wave filter L6, put
After big device F6, varactor doubler, believe with the echo of the 217.56GHz～222.48GHz received by Terahertz reception antenna module
Number carry out being mixed the secondary intermediate frequency output for obtaining 1080MHz.
Preferably, the Terahertz dual-mode antenna module includes terahertz sources antenna and Terahertz reception antenna；Using
When cloud is surveyed on high mountain mountain top, the form of terahertz sources antenna and Terahertz reception antenna is Cassegrain antenna, Cassegrain
Antenna gain is 50dBi, and beam angle is not more than 0.7 °；When being applied to simulate cloud chamber, terahertz sources antenna and Terahertz connect
The form for receiving antenna is electromagnetic horn, and the receiving antenna gain in electromagnetic horn is 30dBi, and beam angle is 8 °.Electromagnetic horn
In transmitter antenna gain (dBi) be 20dBi, beam angle be 15 °.
Preferably, the terahertz signal processing module includes analog-digital converter, memorizer A, memorizer B, FPGA, DSP
And Gigabit Ethernet module；Analog-digital converter, memorizer B, DSP and Gigabit Ethernet module are connected with FPGA, memorizer A with
DSP is connected；Analog-digital converter adopts AD9254 chips, FPGA to adopt Altera EP2S90F1020 chips, DSP to adopt
TMS320C6455 chips, memorizer B adopt 128MB SDRAM, memorizer A to adopt 512MB DDR2.
Beneficial effect：
Compared to laser radar and millimetre-wave radar, the Terahertz cloud detection radar system of the present invention employs one group and is applied to
The parameter of cloud detection, can deep enough thin cloud and very thin cloud enter the stereoscopic three-dimensional structure detection racked, so as to can not only cloud be thick, cloud
The macrostructures such as height, the change of cloud layer number, vertical section, additionally it is possible to obtain the microcosmic such as the size of cloud particle, shape, ice water content knot
Structure.
And, closer to cloud particle yardstick, cloud particle reflection echo has more preferable directivity to the wavelength of terahertz signal,
Finer stereoscopic three-dimensional structure detection can be carried out to cloud layer, so as to improve systemic resolution and sensitivity.
Additionally, higher radar frequency causes have more preferable dependency between ice water content (IWC) and reflectance (Z),
The precision of cloud layer ice water content inverting is improve, is monitored and is estimated with clear-air turbulence to carry out the cloud product inverting of more closing to reality
Meter improves basis.
Its using value of the present invention embodies and is：1. the subtle three-dimensional vertical stratification of cloud layer is detected, contributes to recognizing cloud
It is the influencing mechanism for how affecting locality or large scale atmospheric condition and cloud to radiation environment.2. qualitative assessment weather and weather
The effect of Forecast Mode medium cloud, and then improve the quality of weather and climatic prediction.
Description of the drawings
Composition frame charts of the Fig. 1 for Terahertz cloud detection radar system；
Schematic diagrams of the Fig. 2 for Terahertz frequency multiplication link；
Fig. 3 is the schematic diagram of local oscillator module in Terahertz receiver module；
Schematic diagrams of the Fig. 4 for down coversion receives link module (Terahertz internal calibration module)；
Schematic diagrams of the Fig. 5 for terahertz signal processing module.
Specific embodiment
Develop simultaneously embodiment below in conjunction with the accompanying drawings, describes the present invention.
The mid frequency of terahertz signal can be 110GHz, 150GHz, 220GHz, 340GHz, and bandwidth of operation is
300MHz～5GHz (resolution reaches as high as 3cm), power output are 200mW～100W, and pulse width is 100ns～3 μ s (steps
A length of 100ns), pulse recurrence frequency (PRF) is 1～10KHz (step-length is 1KHz).
The characteristics of parameter of Terahertz radar system is needed for cloud is made a concrete analysis of and is screened.
(1) determine mid frequency
Different detection frequency ranges are different to the sensitivity of meteorological target.In above-mentioned 110GHz, 150GHz, 220GHz and 340GHz
At atmospheric window, decay relatively small, per kilometer of one-way attenuation is about 5～6dB, and with the increase of height above sea level, greatly
In gas, moisture is reduced rapidly, the atmospheric attenuation of terahertz wave band also rapid decrease, therefore preferential at above-mentioned atmospheric window
Select launching frequency.Meanwhile, 110GHz, 150GHz launch window is longer due to wavelength, and penetrance is too strong, and echo strength is weaker,
The detectivity to thin cloud and very thin cloud cannot be met；And 340GHz atmospheric windows are too high due to tranmitting frequency, current Terahertz
Device development level is limited, therefore is chosen to be with detecting Terahertz radar center frequency of the cloud as main purpose in the present invention
220GHz。
(2) determine power output
When surveying cloud, need in view of radar horizon.In general, the distance that cloud is surveyed on ground is 1000m～1500m,
And the Terahertz radar of the present invention also needs to carry out cloud experiment with measuring in simulation cloud chamber and high mountain mountain top, it is therefore desirable to according to reality
The radar weather equation of border applications distances and formula (1) determines the power output of terahertz signal.
In above formula, parameter is defined as follows：
Pr：The meansigma methodss (W) of the echo power that radar is received
Pt：Radar transmitted pulse power (W)
G：The actual gain (dBi) of radar antenna
θ：Antenna horizontal beam width (rad)
Antennas orthogonal beam angle (rad)
τ：Fire pulse width (s)
λ：Radar operation wavelength (m)
c：Electromagnetic wave propagation speed 3x108(m/s)
K：Decay factor of the electromagnetic wave in spatial transmission
r：Target range (m)
Z：Cloud reflection factor
LΣ：Total link is lost (dB)
ln2：2 natural logrithm, takes 0.69315
In this example, the actual gain of radar antenna can be taken in link budget according to current level of processing
50dBi.Reflectivity factor Z is one and the unrelated YUNSHEN amount of frequency, border cloud layer reflectance in -20dBz between 10dBz,
Non- Precipitation Clouds are in -35dBz or so.For the distance by radar equation of meteorological target, in formula (1), parameters value is as follows：
τ=0.3 μ s
G=50dBi
LΣ=5dB
When radar transmitted pulse power PtFor 200mW when, through coherent accumulation process after, for reflectance is -20dBz's
Cloud layer, detection range meet cloud experiment with measuring demand, therefore Terahertz radar transmission power are chosen to be in the present invention up to 3002 meters
200mW。
In the present embodiment, pulse width be 100ns～3 μ s (adjustable, step-length is 100ns), pulse recurrence frequency (PRF)
For 1KHz～10KHz (adjustable, step-length is 1KHz).
(3) determine bandwidth of operation
System bandwidth of operation is wider, and range resolution ratio is higher.The system is to be applied to survey cloud field, by building to YUNSHEN number
Mould, shows that smaller strip width can improve YUNSHEN number inversion accuracy, but bandwidth reduces the reduction that can cause range resolution ratio, surveying
In cloud application, emphasis needs to ensure YUNSHEN number inversion accuracy.On the basis of trade off bandwidth, range resolution ratio and inversion accuracy index
On, Terahertz radar survey cloud bandwidth of operation is set to into 5GHz, now the range resolution ratio of the system is better than 3cm, can meet survey
Cloud accuracy requirement.
(4) pulse width and pulse recurrence frequency are determined
In the present embodiment, pulse width is 100ns～3 μ s (adjustable, step-length is 100ns), and pulse recurrence frequency (PRF) is
1KHz～10KHz (adjustable, step-length is 1KHz).
(5) receiving sensitivity is better than -80dBm
Receiver sensitivity is the important indicator for reflecting Terahertz cloud detection radar system receptivity, main and receiver
System bandwidth is relevant with system noise factor.According to above-mentioned analysis, when system bandwidth is 5GHz, system noise factor is 12dB
When, the system receiving sensitivity is in theory：
Prmin=-114+10lg Δ f+NF=-114+10lg5+12=-87.41dBm
Wherein, Δ f be system bandwidth of operation, NFFor system noise factor.In actual design, it is considered to environment and device shadow
Sound etc. can affect the receptivity of receiver, therefore Terahertz radar system receiver sensitivity is set to better than -80dBm.
(6) dynamic range is better than 60dB
The requirement of dynamic range depends primarily on the excursion of the signal power that receiver is received.In the system, connect
Receipts machine dynamic range is mainly affected by cloud layer reflectivity factor Z, and reflectivity factor Z is one and the unrelated YUNSHEN amount of frequency, side
, in -20dBz between 10dBz, non-Precipitation Clouds are in -35dBz or so for boundary's cloud layer reflectance.Consider the cloud layer that the system is mainly detected
Reflectance is that -40dBz turns to 50dB to the received signal power change between 10dBz, thus causing；While antenna part, feeder line
Change in gain of the part in broadband is about 3～5dB.As fully visible, the change of received signal power is about 53～55dB, because
This is set to Terahertz radar system receiver dynamic range better than 60dB.
Selected based on above-mentioned parameter, with reference to Fig. 1, the ground Terahertz radar system provided by the present invention for surveying cloud is concrete
Including terahertz sources module, Terahertz receiver module, Terahertz dual-mode antenna module, terahertz signal processing module and upper
Machine module.
Terahertz sources module, the intermediate-freuqncy signal source for being produced using Terahertz receiver module complete terahertz signal
Produce and power amplification, then launched by Terahertz dual-mode antenna module.The center of the terahertz signal launched
Frequency is 220GHz, and bandwidth of operation is 5GHz, and transmission power is 200mW, and pulse width is that (adjustable, step-length is 100ns～3 μ s
100ns), pulse recurrence frequency is 1KHz～10KHz (adjustable, step-length is 1KHz).
Terahertz receiver module, for completing the generation of derived reference signal, the generation of intermediate-freuqncy signal source, receiving and dispatching to Terahertz
The down coversion and secondary IF process of the Terahertz echo-signal that Anneta module is received, is then sent to terahertz signal and processes mould
Block.The mid frequency of the Terahertz receiver module is 220GHz, and bandwidth of operation is 5GHz, and receiving sensitivity is better than -80dBm, dynamic
State scope is better than 60dB.
Terahertz signal processing module, for realizing collection, storage and the process of the secondary intermediate-freuqncy signal of Terahertz echo.
Upper computer module is communicated with terahertz signal processing module and Terahertz receiver module respectively, to realize data
Transmission and the comprehensive control of frequency.
In order to realize precision controlling, the present invention also includes Terahertz internal calibration for the ground Terahertz radar system for surveying cloud
Module.As shown in figure 1, the Terahertz internal calibration module obtains the terahertz signal of transmitting from terahertz sources module, and it is right
Which is carried out and Terahertz receiver module identical down-converted, and being then sent to Terahertz receiver module is carried out at secondary intermediate frequency
Reason, the secondary intermediate-freuqncy signal of internal calibration of acquisition are sent to terahertz signal processing module；Terahertz signal processing module is further
Whether offset according to the transmission power and frequency of the secondary intermediate-freuqncy signal inspection terahertz sources signal of internal calibration, according to transmission power
Deviant adjusts the amplifying power of terahertz sources module, offsets the intermediate-freuqncy signal source of adjustment Terahertz receiver module according to frequency
Generation.
Realization to each comprising modules in Terahertz radar system in ground of the present invention below in conjunction with the accompanying drawings is retouched in detail
State.
◎ terahertz sources modules
As shown in figure 1, terahertz sources module includes Terahertz frequency multiplication link, Terahertz power amplifier, bonder.Its
In,
Terahertz frequency multiplication link, for the intermediate-freuqncy signal source frequency multiplication that Terahertz receiver module is produced is obtained Terahertz frequency range
Signal.
This Terahertz frequency multiplication link to realize frequency for 220GHz, bandwidth of operation be 5GHz, and output up to 10mW with
On, it is very high to the requirement of the Primary Components such as high frequency power amplifier, diode, while Terahertz frequency multiplication source can not be using high order times
Frequently, frequency multiplication mode have × 2 × 2 × 3 and × 3 × 2 × 2 two ways it is optional.The frequency relation of × 2 × 2 × 3 frequency multiplication modes is
18.3GHz → 36.6GHz → 73.3GHz → 220GHz, compared to × 3 × 2 × 2 frequencys multiplication, which drives 73.3GHz in prime
There is preferable power amplifier chip in band limits, its output can use power synthetic technique to realize higher driving
Power；In link, maximum power output is about 300mW simultaneously, and current diode can bear, additionally, × 2 × 2 × 3 frequency multiplication sides
Co-volume is little, low in energy consumption, can meet system requirements.Therefore, as shown in Fig. 2 Terahertz frequency multiplication link in the present embodiment is adopted
With × 2 × 2 × 3 frequency multiplication cascade systems realize, receive first from Terahertz receiver module frequency be 18.33 ±
The local oscillation signal of 0.208GHz, power for 0dBm, by an E wave band quadrupler (being made up of two varactor doublers) and one
E band filters obtain the output of 73.2 ± 0.832GHz, then 73.2 are obtained through E band power synthesizers ±
The output of 0.832GHz, power about 300mW, finally drives 220GHz frequency triplers, frequency tripling finally to realize 220 ± 2.5GHz,
Power is the transmission signal of 10mW, is transmitted to Terahertz power amplifier.
Wherein, E wave bands quadrupler is made up of two varactor doublers, is Ka varactor doublers and E wave band varactor doublers respectively,
18.33 ± 0.208GHz local oscillation signals frequency multiplication is that frequency is believed for 36.666GHz ± 0.416GHz by Ka varactor doublers (HMC598)
Number, then by the signal that E wave band varactor doubler (CHU3277) frequencys multiplication are 73.333GHz ± 0.832GHz.
Terahertz power amplifier, for the terahertz signal that Terahertz frequency multiplication link is exported is carried out power amplification, with
The operating distance of increase radar.Terahertz power amplifier realizes big bandwidth using folded waveguide travelling-wave tube amplifier, and (5GHz divides
Resolution 3cm), the power output of 200mW.
Bonder, for the signal output that produces Terahertz power amplifier to Terahertz dual-mode antenna module and terahertz
Hereby internal calibration module.
◎ Terahertz receiver modules
As shown in figure 1, Terahertz receiver module includes that referrer module, secondary ifd module, local oscillator module and down coversion connect
Receive link module.In the present embodiment, Terahertz receiver module mid frequency be 220GHz, bandwidth of operation be 5GHz, receive spirit
Sensitivity is better than 60dB better than -80dBm, dynamic range.
Referrer module, for producing reference frequency source for Terahertz receiver module, reference frequency source is 100MHz.
Local oscillator module, for being that Terahertz receiver module and terahertz sources module produce intermediate-freuqncy signal source.Such as Fig. 3 institutes
Show, local oscillator module is by the Frequency Hopping Signal (being produced by frequency hopping synthesizer module generator) by 2.18～3.203GHz (step-length is 1MHz)
It is divided into two-way after amplifier F0 and power splitter G1 is processed, sequentially passes through wave filter L1, amplifier F1, frequency mixer H1 all the way
The signal output of 1 17.83～18.853GHz of tunnel is produced after (being mixed with 15.65GHz), wave filter L2, amplifier F2 process；Work(
Another road signal that device G1 is produced after processing is divided to sequentially pass through wave filter L3, amplifier F3, frequency mixer H2 (mixed with 15.56GHz
Frequently after), wave filter L4, amplifier F4 are processed, Jing is produced the signal output of 2 17.74～18.763GHz of tunnel by power splitter G2；Wherein
The signal output of 17.83～18.853GHz gives terahertz sources module, used as the intermediate-freuqncy signal source of terahertz sources module；
The signal output of 17.74～18.763GHz to down coversion receives link module and Terahertz internal calibration module, as down coversion
The intermediate-freuqncy signal source of receives link module and Terahertz internal calibration module.
Down coversion receives link module, for the Terahertz thunder obtained to reception antenna in Terahertz dual-mode antenna module
Down coversion is carried out up to cloud echo signal is surveyed, as shown in figure 4, the signal output of the 17.74～18.763GHz produced from local oscillation signal
Extract 18.04～18.45GHz signal through frequency tripler, wave filter L5, amplifier F5, wave filter L6, amplifier F6, two
After doubler, carry out being mixed with the echo-signal of 217.56～222.48GHz received by Terahertz reception antenna module
To an intermediate frequency output of 1080MHz.
Secondary ifd module, exports for the 1080MHz by Terahertz receives link module or Terahertz internal calibration module
The 1020MHz signals produced with fixed local vibration source carry out mixing and obtain bis- intermediate-freuqncy signals of 60MHz, export at terahertz signal
Reason module.
◎ Terahertz dual-mode antenna modules
Terahertz dual-mode antenna module includes terahertz sources antenna, Terahertz reception antenna.
In this example, Terahertz radar needs to carry out cloud experiment with measuring in simulation cloud chamber and high mountain mountain top.On high mountain mountain
During top, the form of Terahertz dual-mode antenna is Cassegrain antenna, and according to the discussion of formula (1), Cassegrain antenna gain is
50dBi, beam angle are not more than 0.7 °.When cloud chamber is simulated, the size of cloud chamber is 3.5m × 3.5m, Terahertz dual-mode antenna
Form is electromagnetic horn, and the receiving antenna gain in electromagnetic horn is 30dBi, and beam angle is 8 °.Transmitting in electromagnetic horn
Antenna gain is 20dBi, and beam angle is 15 °.
◎ Terahertz internal calibration modules
The structure of Terahertz internal calibration module is identical with the structure of down coversion receives link module.As shown in figure 4, Terahertz
Internal calibration module by 18.04～18.45GHz signal through frequency tripler, wave filter L5 ', amplifier F5 ', wave filter L6 ',
The 220GHz terahertz sources signals obtained in bonder after amplifier F6 ', varactor doubler and from terahertz sources module
The intermediate frequency output that down coversion obtains 1080MHz, and the secondary ifd module in exporting to Terahertz receiver module are carried out, is obtained
Bis- intermediate-freuqncy signals of 60MHz, export and give terahertz signal processing module.
◎ terahertz signal processing modules
Collection, storage and the process of the secondary intermediate-freuqncy signal of terahertz signal processing modules implement Terahertz echo.
Terahertz signal processing module realizes terahertz always according to the internal calibration intermediate-freuqncy signal from Terahertz internal calibration module
The hereby periodic internal calibration and adjustment of cloud detection radar system, detection terahertz sources module, the drift of Terahertz receiver module,
To ensure the stability and accuracy of Terahertz cloud detection radar system.Specifically according to the secondary intermediate-freuqncy signal inspection of internal calibration
Whether the transmission power and frequency of terahertz sources signal offsets, and adjusts terahertz sources module according to transmission power deviant
Amplifying power, offsets the generation of the intermediate-freuqncy signal source of adjustment Terahertz receiver module according to frequency.
As shown in figure 1, the terahertz signal processing module includes analog-digital converter (AD), memorizer A, memorizer B, scene
Programmable gate array (FPGA), digital signal processor (DSP), Gigabit Ethernet module.Analog-digital converter, memorizer B, numeral
Signal processor and Gigabit Ethernet module are connected with field programmable gate array, memorizer A and digital signal processor phase
Even.
As shown in figure 5, analog-digital converter adopts AD9254 chips, 14bit (bit) is realized, (million samplings are every for 150MSPS
Second) data acquisition ability, realize being not less than using Altera EP2S90F1020 (FPGA) and TMS320C6455 (DSP)
The operational capability of 9600MMACS (million multiply-add operations are per second), the plug-in 512MB of the plug-in 128MB SDRAM of FPGA, DSP
DDR2。
◎ upper computer modules
Upper computer module passes through gigabit Ethernet and serial ports receives mould with terahertz signal processing module and Terahertz respectively
Block is communicated, to realize data transfer with the comprehensive control of frequency.Upper computer module includes computer main board, display, realize control with
Display function.
In sum, presently preferred embodiments of the present invention is these are only, is not intended to limit protection scope of the present invention.
All any modification, equivalent substitution and improvements within the spirit and principles in the present invention, made etc., should be included in the present invention's
Within protection domain.
Claims (5)
1. a kind of ground Terahertz radar system for surveying cloud, it is characterised in that include：Terahertz sources module, Terahertz
Receiver module, Terahertz dual-mode antenna module, terahertz signal processing module, upper computer module and Terahertz internal calibration mould
Block；
Terahertz sources module, the intermediate-freuqncy signal source for being produced using Terahertz receiver module complete the generation of terahertz signal
With power amplification, then launched by Terahertz dual-mode antenna module；The mid frequency of the terahertz signal launched
For 220GHz, bandwidth of operation is 5GHz, and transmission power is 200mW, and pulse width is adjustable in the range of the μ s of 100ns～3 and regulation
Step-length is 100ns, and pulse recurrence frequency is adjustable in the range of 1KHz～10KHz and regulation step-length is 1KHz；
Terahertz receiver module, for completing the generation of derived reference signal, the generation of intermediate-freuqncy signal source, to Terahertz dual-mode antenna
The down coversion and secondary IF process of the Terahertz echo-signal that module is received, is then sent to terahertz signal processing module；
The mid frequency of the Terahertz receiver module is 220GHz, and bandwidth of operation is 5GHz, and receiving sensitivity is better than -80dBm, dynamic model
Enclose better than 60dB；
Terahertz signal processing module, for realizing collection, storage and the process of the secondary intermediate-freuqncy signal of Terahertz echo；
Upper computer module is communicated with terahertz signal processing module and Terahertz receiver module respectively, to realize data transfer
With the comprehensive control of frequency；
Terahertz internal calibration module obtains the terahertz signal of transmitting from terahertz sources module, and which is carried out and Terahertz
Receiver module identical down-converted, being then sent to Terahertz receiver module carries out secondary IF process, acquisition it is default
Mark secondary intermediate-freuqncy signal and be sent to terahertz signal processing module；Terahertz signal processing module is further secondary according to internal calibration
Whether the transmission power and frequency of intermediate-freuqncy signal inspection terahertz sources signal offsets, and adjusts terahertz according to transmission power deviant
Hereby the amplifying power of transmitter module, offsets the generation of the intermediate-freuqncy signal source of adjustment Terahertz receiver module according to frequency；
The Terahertz receiver module includes referrer module, secondary ifd module, local oscillator module and down coversion receives link module；
Referrer module, for producing reference frequency source for Terahertz receiver module, reference frequency source is 100MHz；
Local oscillator module, for being that Terahertz receiver module and terahertz sources module produce intermediate-freuqncy signal source；The local oscillator module
By the Frequency Hopping Signal of 2.18GHz～3.203GHz is divided into two-way after amplifier F0 and power splitter G1 are processed, all the way according to
The secondary L1 of device after filtering, amplifier F1, frequency mixer H1, wave filter L2, amplifier F2 process after produce 1 road 17.83GHz～
18.853GHz signal output；After power splitter G1 process another road signal for producing sequentially pass through wave filter L3, amplifier F3,
Frequency mixer H2, wave filter L4, amplifier F4 process after Jing by power splitter G2 produce 2 road 17.74GHz～18.763GHz signal
Output；Wherein the signal output of 17.83GHz～18.853GHz gives terahertz sources module, used as in terahertz sources module
Frequency source signal；The signal output of 17.74GHz～18.763GHz is to down coversion receives link module and Terahertz internal calibration mould
Block, as down coversion receives link module and the intermediate-freuqncy signal source of Terahertz internal calibration module；
Down coversion receives link module, the Terahertz radar for being obtained to reception antenna in Terahertz dual-mode antenna module are surveyed
Cloud echo signal carries out down coversion；
Secondary ifd module, for the 1080MHz outputs by Terahertz receives link module or Terahertz internal calibration module and admittedly
The 1020MHz signals for determining local vibration source generation carry out mixing and obtain bis- intermediate-freuqncy signals of 60MHz, export and process mould to terahertz signal
Block.
2. the system as claimed in claim 1, it is characterised in that the terahertz sources module include Terahertz frequency multiplication link,
Terahertz power amplifier and bonder；
The Terahertz frequency multiplication link, for the intermediate-freuqncy signal source frequency multiplication that Terahertz receiver module is produced is obtained Terahertz frequency range
Signal；Frequency multiplication is realized using the cascade system of two+two frequencys multiplication of frequency multiplication+frequency tripling：Receive Terahertz receiver module first to provide
Frequency be 18.33GHz ± 0.208GHz, power for 0dBm signal, by the E wave bands four of two varactor doubler composition
Doubler and E band filter obtain the output of 73.2GHz ± 0.832GHz, then obtain through E band power synthesizers
It is the output of 300mW to 73.2GHz ± 0.832GHz, power, finally drives 220GHz frequency triplers, it is finally real by frequency tripler
Existing 220GHz ± 2.5GHz, power are the transmission signal of 10mW, are transmitted to Terahertz power amplifier；
Wherein, E wave bands quadrupler is made up of two varactor doublers, is Ka varactor doublers and E wave band varactor doublers respectively, Ka bis-
Doubler by the signal frequency multiplication of 18.33GHz ± 0.208GHz be frequency be 36.666GHz ± 1GHz signals, then by two times of E wave bands
Signal of the frequency device frequency multiplication for 73.333GHz ± 0.832GHz；
Terahertz power amplifier, for the terahertz signal that Terahertz frequency multiplication link is exported is carried out power amplification；
Bonder, for the signal output that produces Terahertz power amplifier in Terahertz dual-mode antenna module and Terahertz
Scaling module.
3. the system as claimed in claim 1, it is characterised in that the down coversion receives link module, produces from local oscillation signal
17.74GHz～18.763GHz signal output extract 18.04GHz～18.45GHz signal through frequency tripler, filtering
After device L5, amplifier F5, wave filter L6, amplifier F6, varactor doubler, and received by Terahertz reception antenna module
The echo-signal of 217.56GHz～222.48GHz carries out being mixed the secondary intermediate frequency output for obtaining 1080MHz.
4. the system as claimed in claim 1, it is characterised in that the Terahertz dual-mode antenna module includes terahertz sources day
Line and Terahertz reception antenna；
When being applied to high mountain mountain top survey cloud, the form of terahertz sources antenna and Terahertz reception antenna is Cassegrain antenna,
Cassegrain antenna gain be 50dBi, beam angle be not more than 0.7 °；
When being applied to simulate cloud chamber, the form of terahertz sources antenna and Terahertz reception antenna is electromagnetic horn, electromagnetic horn
In receiving antenna gain be 30dBi, beam angle be 8 °；Transmitter antenna gain (dBi) in electromagnetic horn be 20dBi, beam angle
For 15 °.
5. the system as claimed in claim 1, it is characterised in that the terahertz signal processing module include analog-digital converter,
Memorizer A, memorizer B, FPGA, DSP and Gigabit Ethernet module；Analog-digital converter, memorizer B, DSP and gigabit Ethernet mould
Block is connected with FPGA, and memorizer A is connected with DSP；
Analog-digital converter adopts AD9254 chips, FPGA to adopt Altera EP2S90F1020 chips, DSP to adopt
TMS320C6455 chips, memorizer B adopt 128MB SDRAM, memorizer A to adopt 512MB DDR2.
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| CN106817124A (en) * | 2015-11-30 | 2017-06-09 | 中国科学院物理研究所 | Terahertz signal generator based on spintronics devices |
| CN106896081A (en) * | 2015-12-21 | 2017-06-27 | 中国科学院物理研究所 | THz wave meteorological detection device |
| CN106921347A (en) * | 2015-12-28 | 2017-07-04 | 中国科学院物理研究所 | For the upconverter based on spin oscillator of GSM |
| CN106019246B (en) * | 2016-04-08 | 2018-08-17 | 中国工程物理研究院电子工程研究所 | A kind of active Terahertz quick security check instrument real-time correction method based on internal object |
| CN107064956B (en) * | 2016-11-17 | 2019-11-08 | 上海无线电设备研究所 | A kind of ground Terahertz cloud detection radar system and its detection method |
| CN106597404B (en) * | 2016-11-29 | 2019-06-14 | 上海无线电设备研究所 | Terahertz cloud method for processing radar signals and system |
| CN107017902B (en) * | 2017-05-23 | 2022-11-29 | 中国电子科技集团公司第十三研究所 | 220GHz receiver based on MEMS technology |
| CN106992792B (en) * | 2017-05-23 | 2023-06-27 | 中国电子科技集团公司第十三研究所 | 220GHz terahertz transmitter based on MEMS technology |
| CN109282896B (en) * | 2017-07-23 | 2020-08-18 | 北京遥感设备研究所 | Heterodyne reception-based terahertz power measurement system |
| CN110907924A (en) * | 2018-09-18 | 2020-03-24 | 雄安华讯方舟科技有限公司 | Signal conversion device of terahertz radar and terahertz radar |
| CN109490624B (en) * | 2018-10-19 | 2020-11-10 | 陕西长岭电子科技有限责任公司 | Pulse signal frequency measurer |
| CN109884640A (en) * | 2019-02-20 | 2019-06-14 | 北京市人工影响天气办公室 | A kind of data processing method, device and electronic equipment |
| CN109975882A (en) * | 2019-04-28 | 2019-07-05 | 软通智慧科技有限公司 | Detection device and security inspection equipment |
| CN111289963A (en) * | 2020-02-29 | 2020-06-16 | 哈尔滨吉赫科技有限责任公司 | Continuous millimeter wave terahertz ultra-wideband noise radar |
| CN112068222B (en) * | 2020-08-24 | 2022-06-28 | 国家卫星气象中心(国家空间天气监测预警中心) | Foundation terahertz signal generation method for calibrating visual axis of multi-frequency terahertz detector |
| CN111969955B (en) * | 2020-08-27 | 2023-05-09 | 中电科思仪科技股份有限公司 | Waveguide transmission line-based 0.5-0.75 THz broadband high-efficiency solid source and working method thereof |
| CN113325417B (en) * | 2021-05-24 | 2024-03-15 | 西安空间无线电技术研究所 | Millimeter wave and terahertz multi-band radar detection imaging system and method |
| CN113608175B (en) * | 2021-08-03 | 2023-09-19 | 上海无线电设备研究所 | RCS measurement receiving and transmitting system based on quantum cascade |
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| CN102707273B (en) * | 2012-06-27 | 2013-08-14 | 电子科技大学 | THz radar transmitting/receiving front end |
| WO2014097756A1 (en) * | 2012-12-19 | 2014-06-26 | 古野電気株式会社 | Radar system |
| CN103592640A (en) * | 2013-11-20 | 2014-02-19 | 中国船舶重工集团公司第七二四研究所 | Automatic high-precision calibration method of meteorological radar send-receive channel gains |
| CN103592641A (en) * | 2013-11-22 | 2014-02-19 | 北京无线电测量研究所 | Device for measuring transmitting power of millimeter wave cloud radar in real time |
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