CN207318707U - A kind of calibration circuit of fmcw radar phase stabilization - Google Patents
A kind of calibration circuit of fmcw radar phase stabilization Download PDFInfo
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- CN207318707U CN207318707U CN201721421463.0U CN201721421463U CN207318707U CN 207318707 U CN207318707 U CN 207318707U CN 201721421463 U CN201721421463 U CN 201721421463U CN 207318707 U CN207318707 U CN 207318707U
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Abstract
Radar electric circuit field is the utility model is related to, more particularly to a kind of calibration circuit of fmcw radar phase stabilization, the calibration circuit includes：Signal feedback circuit, signal transmission circuit, transmitting antenna, signal receiving circuit, reception antenna, signal processing module；The signal feedback circuit, including two directional couplers and an adjustable attenuator.Pass through the measurement data of each frame of signal, by the echometric measurement result of measured target compared with the measurement result of calibration signal, to eliminate the phase fluctuation of the signal transmission circuit and the signal receiving circuit, the deformation phase difference of accurate measured target is obtained.Real time calibration dynamically can be carried out from signal phase fluctuation caused by environment and time change of experiencing to radar signal circuit and signal receiving circuit by the utility model, improve the precision of detection.
Description
Technical field
A kind of radar electric circuit is the utility model is related to, particularly a kind of calibration circuit of fmcw radar phase stabilization.
Background technology
In recent years, urban transportation development in China's is rapid, and volume of transport greatly improves so that across river crossing bridge and
Importance of the overpass in urban transportation is growing day by day.With the overload clothes that exceed the time limit increased with numerous bridges of bridge construction
Labour, the bridge that constantly collapses, damage bridge accident, cause many casualties and huge property loss, therefore the regular deformation prison of bridge
Survey and health, safety evaluation are particularly important.By the discovery of early stage bridge defect, the dimension of bridge can be greatlyd save
Repair expense, can to avoid heavy losses caused by frequent overhaul close traffic, and to greatest extent reduce Bridge Accidents caused by
Loss.
Ground interferometer radar system application linear frequency modulation continuous wave (FMCW) and microwave interference e measurement technology, can obtain mesh
Mark deformation data of the band radar sight to one-dimensional distance domain.Compared to traditional geodesic survey such as Levelling, total powerstation and GPS
Deformation monitoring method, ground interferometer radar need not have with observed object region directly to be contacted, by the meteorological conditions such as cloud and mist wet weather,
The influence of adverse circumstances is smaller, and higher sample rate is respectively provided with time domain and spatial domain, in the deformation of the linear target such as bridge
There is good application prospect in monitoring.
Radar sensor carries out continuous sampling to monitoring objective region, and extraction is calculated by the interference between neighbouring sample signal
Deformation phase, and then calculate deformation quantity.Radar line of sight to deformation quantity D and deformation phase difference φ meet following relation：
Wherein, λ is the wavelength of radar emission signal.Δ φ be radar transmitting wave in testee in the front and rear institute that deforms
Reach the signal phase change of receiving terminal, that is, phase difference.
By formula (1) as it can be seen that after radar transmitter frequency i.e. wavelength determine, the object deformation quantity that can be detected is with regard to only
It is related to the signal phase change precision that radar receiving terminal detects.
For example, when radar emission signal is 20GHz, corresponding wavelength is 15mm.When testee causes
Received wave when being tested with 1 ° of phase place change, illustrate that the shape of testee is changed into：
With reference to Fig. 1, in actual radar circuit, it is known that transmitting signal phase be namely to launch DA positioned at intermediate frequency to produce
Raw signal phase, the phase of echo of measurement are the signal phases that intermediate frequency namely receives AD acquisitions.Therefore the two phases
Difference not only has the phase place change that the deformation band of actual testee comes, and also has the transmission of signal transmission circuit and signal receiving circuit
Phase.It is generally acknowledged that the transmission phase of signal transmission circuit and signal receiving circuit is stable, so the transmitting of measurement and connecing
The phase difference of the collection of letters number i.e. the deformation phase place change of testee.But signal transmission circuit and signal receiving circuit
It is changeless to transmit phase not being, it can be influenced to change by factors such as voltage, temperature, especially for measurement ultra micro
The phase place change of the phase place change in the several years required by deformation, signal transmission circuit and signal receiving circuit can be far longer than this
Magnitude, in this way, the accuracy of detection of radar will be greatly reduced.
Utility model content
The goal of the invention of the utility model is：Complete to calibrate the phase place change of radar emission circuit and receiving circuit,
Improve accuracy of detection of the radar to phase parameter.A kind of therefore it provides calibration circuit of fmcw radar phase stabilization.
In the embodiment of the utility model, a kind of calibration circuit of fmcw radar phase stabilization, including：Signal feedback electricity
Road, signal transmission circuit, transmitting antenna, signal receiving circuit, reception antenna, signal processing module；
The signal feedback circuit, including the first directional coupler, adjustable attenuator, the second directional coupler, first is fixed
The signal transmission circuit is connected to the first port of coupler, second port connects the transmitting antenna, and the 3rd port passes through
Connect one end of the adjustable attenuator；The first port of second directional coupler connects the reception antenna, and second port connects
The signal receiving circuit is connect, the 3rd port connects the other end of the adjustable attenuator.
The signal processing module and signal transmission circuit, signal receiving circuit connect at the same time.
According to one embodiment, the signal transmission circuit, including sequentially connected signal generating circuit, filter circuit,
Mixing and filtering circuit, power amplification circuit；
The power amplification circuit connects the first port of first directional coupler.
According to one embodiment, the signal receiving circuit, including sequentially connected pre-amplification circuit, mixing and filtering electricity
Road, video amplifier circuit, zero intermediate frequency output circuit；
The pre-amplification circuit connects the second port of second directional coupler；
The zero intermediate frequency output circuit connects the signal processing module.
According to one embodiment, the signal processing module, including sequentially connected ADC acquisition modules, filtering extraction mould
Block, phase and amplitude and orthogonality calibration module, coherent accumulation module, permanent empty scape module, real time calibration module, data output
Module.
In conclusion by adopting the above-described technical solution, the beneficial effects of the utility model are：
1st, technological means is simple, it is only necessary to increases calibration loop in pervious radar system, and holds after signal processing
Improve real time calibration module.
2nd, effectively reduce because each device is because temperature drift, frequency inside signal transmission circuit and signal receiving circuit
Drift and caused by measurement error.
3rd, for measurement building moving and deformation, bridge displacement, the natural phenomena such as including landslide is realized with deformation
High-acruracy survey；Through overtesting, using the measurement result of calibration signal compared with without using calibration signal, measurement result at least carries
High 1 to 2 orders of magnitude, effectively realize and detection are carried out an acceptance inspection to building, bridge and carries out risk assessment, the measurement to massif has
Effect avoids injury of the natural calamity to the mankind.
Brief description of the drawings
Fig. 1 is existing radar electricity functional block diagram.
Fig. 2 is the circuit diagram of the utility model embodiment.
Fig. 3 is the system detailed schematic block diagram of the utility model embodiment.
Marked in figure：The first directional couplers of 1-, 2- transmitting antennas, 3- adjustable attenuators, the second directional couplers of 4-, 5-
Reception antenna.
Embodiment
In order to make the purpose of the utility model, technical solutions and advantages more clearly understood, below in conjunction with attached drawing and implementation
Example, is further elaborated the utility model.It should be appreciated that specific embodiment described herein is only explaining this
Utility model, is not used to limit the utility model.
With reference to the calibration circuit of Fig. 2, the utility model embodiment a kind of fmcw radar phase stabilization provided, including：Letter
Number feedback circuit, signal transmission circuit, transmitting antenna 2, signal receiving circuit, reception antenna 5, signal processing module；
The signal feedback circuit, including the first directional coupler 1, adjustable attenuator 3, the second directional coupler 4, first
The first port of directional coupler 1 connects the signal transmission circuit, and second port connects the transmitting antenna 2, the 3rd port
By the one end for connecting the adjustable attenuator 3；The first port connection reception antenna 5 of second directional coupler 4, second
Port connects the signal receiving circuit, and the 3rd port connects the other end of the adjustable attenuator 3.
The signal processing module and signal transmission circuit, signal receiving circuit connect at the same time.
With reference to Fig. 3, the signal transmission circuit, including sequentially connected signal generating circuit, filter circuit, mixing and filtering
Circuit, power amplification circuit；
The power amplification circuit connects the first port of first directional coupler 1.
The signal receiving circuit, including sequentially connected pre-amplification circuit, mixing and filtering circuit, video amplifier electricity
Road, zero intermediate frequency output circuit；
The pre-amplification circuit connects the second port of second directional coupler 4.
The signal processing module, including sequentially connected ADC acquisition modules, filtering extraction module, phase and amplitude with
And orthogonality calibration module, coherent accumulation module, permanent empty scape module, real time calibration module, data outputting module.
The course of work of the calibration circuit provided below in conjunction with the utility model embodiment further illustrates：
(1) signal transmission circuit is generated and transmitted by signal；
(1.1) signal produces：Signal generating circuit produces synchronous low-frequency chirp continuous wave as radar signal；It is whole
It is a calibration the circuit course of work clock use same clock source so that each functional circuit it is identical with the clock of module or
Into integral multiple relation, the asynchronous systematic error brought of clock is avoided；
(1.2) filter：Interference signal in radar signal is reduced by filter circuit；
(1.3) mixing and filtering：The radar signal of low frequency is converted to the radar signal of high frequency by mixing and filtering circuit, with
Meet measurement of micromovements required precision, and radar signal is filtered again, remove interference signal；
(1.4) power amplification：By power amplification circuit by the power amplification of radar signal to 1W or 10W even bigger,
Meet the measurement of distant object with this；
(2) signal receiving circuit receives signal；
Radar signal is inputted by the first port of the first directional coupler 1, is exported from second port to the transmitting day
Line 2 is launched, and is considered as measuring signal, while radar signal is exported from the 3rd port, is considered as calibration signal (calibration signal power meeting
Less than the measuring signal), the measuring signal is back to the reception antenna 5 after measured target, is considered as measurement letter
Number echo, the measuring signal echo inputs 4 first port of the second directional coupler, while calibration signal passes through adjustable attenuator
3 inputs are considered as calibration signal echo, the calibration signal echo is fixed by second to the 3rd port of the second directional coupler 4
Coupled to coupler 4 with measuring signal echo, be considered as echo-signal, the echo-signal is from 4 second end of the second directional coupler
Mouth is exported to signal receiving circuit；
Since power reduces after the measured target of measuring signal, calibration signal work(is suitably reduced by adjustable attenuator 3
Rate improves calibration effect with conjunction measuring signal echo；
(2.1) preposition amplification：It is low noise amplifier circuit by pre-amplification circuit, while amplified signal, reduces
Noise jamming；The pre-amplification circuit is low noise amplifier circuit；
(2.2) mixing and filtering：By mixing and filtering, from high frequency conversion it is low frequency by echo-signal, and removes interference signal；
(2.3) video amplifier：Video amplifier is carried out to echo-signal, the video amplifier uses sensitivity frequency control
(i.e. usually used SFC, sensitivity frequency control) is designed, to realize to remote echo signal times magnification
Number is big, small to close-target amplification factor so that the calibration circuit of the present embodiment can meet to measure remote, close-target；
(2.4) zero intermediate frequency exports：Small bandwidth filtering is carried out by zero intermediate frequency output to echo-signal to export to signal again
Manage module；
(3) signal processing module carries out signal calibration and exports；The signal processing module adds DSP architecture using FPGA；
(3.1) ADC is gathered：Echo-signal at this time is analog signal, can not carry out Digital Signal Processing, be adopted by ADC
Collect module, echo-signal is converted from analog into digital signal, and carry out signal acquisition, in this design using low communication
Number collection, the collection clock be more than nyquist sampling theorem required by clock, collecting efficiency can be improved；It is and described
The collection clock of ADC acquisition modules, using the clock signal homologous with signal generating circuit, specially using signal generating circuit
Clock of the output as ADC collections after clock division, can effectively reduce the measurement error of collection clock zone；
(3.2) filtering extraction：While improving collecting efficiency by ADC acquisition modules, gathered data amount is relatively large, because
This reduces the data volume by filtering extraction module；
(3.3) phase and amplitude and orthogonality calibration：The is carried out by phase and amplitude and orthogonality calibration module
One calibrated section：The echo-signal of collection is due to the reason such as device factor, the inconsistency of hardware circuit, from signal receiving circuit
Input gathers this process to ADC, and the parameter such as the amplitude of echo-signal, phase, orthogonality can impacted, reduction measurement result,
Therefore, the amplitude, phase, the orthogonality that gather signal are measured in each measurement, and the compensation of corresponding compensating parameter is arrived
In corresponding echo-signal, influence of the circuit to signal measurement is reduced.
(3.4) coherent accumulation：It is a frame data by the multiframe Data Integration of echo-signal by coherent accumulation module：Mesh
Echo signal power is marked with being more big changes according to the size of target range and target reflecting section, when target is close, reflecting surface
When very big, echo power can be larger, but target range becomes larger, and after reflecting surface diminishes, power can substantially diminish.Due to the knot of measurement
Fruit be fine motion to target carry out long-time measurement as a result, it can thus be assumed that target is motionless in a short time, or mesh
Mark uses coherent accumulation by the multiframe Data Integration of echo-signal for a frame data from concussion frequency very little, is surveyed with reducing
The random error of result is measured, system sensitivity is improved, improves the accuracy to the measurement result of distant object；
Further, according to coherent accumulation number, measurement result output speed is for hundreds of times per second or tens times or several times
Differ, when the calibration circuit of the present embodiment works, its coherent accumulation module can also be configured coherent accumulation number, with full
Sufficient measurement request；
(3.5) permanent empty scape：By permanent empty scape module, by the too small data of echo signal power and noise remove, further
Reduce data volume；
(3.6) real time calibration：Second calibrated section is carried out by real time calibration module：Echo-signal is by permanent empty scape mistake
Afterwards, data volume is obviously reduced, while the correlation measurements of echo-signal also specifically quantify, therefore can distinguish measuring signal
Echo and calibration signal echo, according to measuring signal, measuring signal echo, calibration signal, calibration signal echo relevant parameter,
Calibration is made to objective measurement, exports final frame data measurement result.
Its calibrating principle is：Due to calibration signal (the phase θ of the first directional coupler 1 output1) and the transmitting day
Measuring signal (the phase Φ of line transmitting1) pass through that transmission path is completely the same, and the receiving circuit receives and passes through letter
Number processing after calibration signal echo (phase θ2) with measured target reflection measuring signal echo (phase Φ2) connect
It is completely the same to receive circuit, uniquely the difference is that echo path is different, therefore can be realized by the detection phase of calibration signal to whole
The phase error of a signal transmission circuit and signal receiving circuit carries out real time calibration.Specially in the measurement data of each frame
In, by measurement result Φ (Φ=Φ of the reflected signal of measured target2-Φ1) with measurement result θ (θ=θ of calibration signal2-
θ1) be compared, to eliminate the phase fluctuation of the signal transmission circuit and the signal receiving circuit, obtain Δ φ (Δ φ
=Φ-θ), the deformation phase difference of the measured target after as calibrating；
(3.7) data export：By data outputting module, packaged data and the deformation quantity D for exporting measured target：Deformation
Amount D and deformation phase difference φ relation be：Wherein, λ is the wavelength of echo-signal, whole calibration electricity
Speed and the cycle of signal are not changed in the course of work of road, therefore λ is constant that (i.e. the wavelength of echo-signal is exactly radar emission signal
Wavelength)；
Further, the data outputting module also carries display control module, to realize the deformation results of measured target
Output and display.
The above is only the preferred embodiment of the utility model only, is not intended to limit the utility model, all at this
All any modification, equivalent and improvement made within the spirit and principle of utility model etc., should be included in the utility model
Protection domain within.
Claims (4)
- A kind of 1. calibration circuit of fmcw radar phase stabilization, it is characterised in that including：Signal feedback circuit, signal transmitting electricity Road, transmitting antenna, signal receiving circuit, reception antenna, signal processing module；The signal feedback circuit, including the first directional coupler, adjustable attenuator, the second directional coupler, the first orientation coupling The first port of clutch connects the signal transmission circuit, and second port connects the transmitting antenna, described in the connection of the 3rd port One end of adjustable attenuator；The first port of second directional coupler connects the reception antenna, and second port connects the letter Number receiving circuit, the 3rd port connect the other end of the adjustable attenuator；The signal processing module and signal transmission circuit, signal receiving circuit connect at the same time.
- 2. calibration circuit according to claim 1, it is characterised in that the signal transmission circuit, including it is sequentially connected Signal generating circuit, filter circuit, mixing and filtering circuit, power amplification circuit；The power amplification circuit connects the first port of first directional coupler.
- 3. calibration circuit according to claim 1, it is characterised in that the signal receiving circuit, including it is sequentially connected Pre-amplification circuit, mixing and filtering circuit, video amplifier circuit, zero intermediate frequency output circuit；The pre-amplification circuit connects the second port of second directional coupler；The zero intermediate frequency output circuit connects the signal processing module.
- 4. calibration circuit according to claim 1, it is characterised in that the signal processing module, including it is sequentially connected ADC acquisition modules, filtering extraction module, phase and amplitude and orthogonality calibration module, coherent accumulation module, permanent empty scape mould Block, real time calibration module, data outputting module.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721421463.0U CN207318707U (en) | 2017-10-30 | 2017-10-30 | A kind of calibration circuit of fmcw radar phase stabilization |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721421463.0U CN207318707U (en) | 2017-10-30 | 2017-10-30 | A kind of calibration circuit of fmcw radar phase stabilization |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110971256A (en) * | 2018-09-29 | 2020-04-07 | 天津大学青岛海洋技术研究院 | FMCW transceiver framework capable of restraining transceiving coupling and supporting high output power |
| CN111103571A (en) * | 2018-10-26 | 2020-05-05 | 德克萨斯仪器股份有限公司 | Method and apparatus for compensating for radar system calibration variations |
| CN112946589A (en) * | 2021-02-01 | 2021-06-11 | 上海交通大学 | Phase self-calibration method for motion measurement of asynchronous FMCW radar system |
-
2017
- 2017-10-30 CN CN201721421463.0U patent/CN207318707U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110971256A (en) * | 2018-09-29 | 2020-04-07 | 天津大学青岛海洋技术研究院 | FMCW transceiver framework capable of restraining transceiving coupling and supporting high output power |
| CN111103571A (en) * | 2018-10-26 | 2020-05-05 | 德克萨斯仪器股份有限公司 | Method and apparatus for compensating for radar system calibration variations |
| CN112946589A (en) * | 2021-02-01 | 2021-06-11 | 上海交通大学 | Phase self-calibration method for motion measurement of asynchronous FMCW radar system |
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