CN2929859Y - Microwave traffic vehicle information detector - Google Patents
Microwave traffic vehicle information detector Download PDFInfo
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- CN2929859Y CN2929859Y CN 200620113150 CN200620113150U CN2929859Y CN 2929859 Y CN2929859 Y CN 2929859Y CN 200620113150 CN200620113150 CN 200620113150 CN 200620113150 U CN200620113150 U CN 200620113150U CN 2929859 Y CN2929859 Y CN 2929859Y
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Abstract
The utility model discloses a microwave traffic detector for checking vehicle information, comprising a microwave portion, a DSP portion for A/D data translation, real-time FFT transformation, calculating vehicle information according to characteristic parameters of the signal in different time, and a digit circuit processing portion consisted of correlation memory units and a circuit for controlling interface portions, wherein the microwave portion is consisted of an emitter circuit for emitting linear frequency modulated microwave signal, a receiving circuit for receiving reflected signals and a microwave antenna, the DSP portion is used for translating A/D data, doing real-time FFT transformation and calculating vehicle information according to characteristic parameters of the signals in different time. The microwave detector of the utility model is capable of providing real-time information about traffic volume, pace, lane occupancy ratio, automobile mode, and the like, and being equipped on column or similar structure along the road, which not only is advanced in technique, convenient in assemblage and maintenance and low in cost, but also does not break pavement and impact traffic.
Description
Technical field
The utility model relates to a kind of Traffic Management Facilities, especially relates to a kind of intelligent traffic vehicle information detector.
Background technology
Along with the continuous evolution and the development of field of traffic, in traffic administration and control, all need to understand various traffic stream characteristics parameters, as: the volume of traffic, occupation rate, car speed etc.The mensuration of the volume of traffic plays an important role to traffic programme, roading design.The mensuration of the speed of a motor vehicle also is a very important part, and it provides speed data for traffic control, is used to determine speed limit, and then traffic sign rationally is set, for traffic punishment provides foundation, for the research of other traffic directions provides the real data resource.At present, the traffic information collection equipment and the system of field of traffic, the main hardware terminal of support is coil and video mode.The coil mode is to bury coil underground to gather traffic information data on the road surface, and coil is very big to the influence of product detecting reliability in installation process, and repairs or install and need suspend traffic, and can influence pavement life in the construction.In use coil is easily repaired damages such as construction by heavy vehicle and road surface.Video mode is subjected to the influence of Changes in weather such as misty rain snow easily, can not round-the-clock work.
Summary of the invention
The purpose of this utility model provides a kind of microwave vehicular traffic information detector, utilizes the noncontact mode with solution, the round-the-clock problems such as real-time information that vehicle on the highway is provided.
The structure of microwave vehicular traffic information detector described in the utility model comprises:
The microwave part: mainly signal circuit and microwave antenna three parts that reflected by the chirped microwave signal circuit of emission, reception are formed, wherein the direction setting of microwave antenna can cover the track that all need detect with the projection that guarantees wave beam, guarantees projection simultaneously and detects the road quadrature; The microwave signal circuit part that makes antenna launch chirped triangular signal is connected with the output terminal of the voltage-frequency translation circuit that produces voltage-controlled concussion driving adjusting triangular signal, and is driven by it; The output terminal of the signal circuit section that reception reflects behind detection, mixting circuit, connects the input end of digital circuit part;
The digital circuit processing section: the A/D data converted is sent into dsp chip through after the data buffering storage, and the data that will calculate flow, vehicle, average velocity and the lane occupancy ratio parameter of vehicle by the output terminal of dsp chip are sent into the corresponding interface place again.
It is chirped control circuit structure that aforesaid a kind of microwave vehicular traffic information detector, microwave transmit and receive, and handles obtaining information of vehicles via dsp processor and interrelated logic device, and this information of vehicles is sent to the circuit of control interface.
Aforesaid a kind of microwave vehicular traffic information detector, the peripheral circuit of described dsp processor mainly comprises the digital flash memories of the driver that stores dsp processor and mainly stores the hardware logic structures such as physical memory device RAM of dsp processor desired parameters information.
The microwave traffic detecting device that the utility model provides is to utilize radar linear frequency modulation know-why, the road pavement launched microwave, by echoed signal being carried out the digitized processing analysis of high-speed real-time, the contactless traffic detecting device of traffic flow essential informations such as inspection vehicle flow, speed, lane occupancy ratio and vehicle.It is mainly used in the traffic parameter collection of highway, city expressway, common road traffic flow investigation station and bridge, and having can be in the round-the-clock advantage that real-time information such as vehicle flowrate, speed, lane occupancy ratio and vehicle are provided.Above-mentioned information can be connected to existing controller or be connected to other system by serial communication line with the isolation contactor, is traffic control and management, and information issue etc. provides the data support.This device can be installed on trackside column or the similar structures, has convenient for installation and maintenancely, need not destroy the road surface, does not influence traffic, advanced technology, characteristics such as cost is low.
Description of drawings
Fig. 1 is range measurement principle figure of the present utility model.
Fig. 2 is triangular wave swept-frequency signal figure of the present utility model.
Fig. 3 is a FFT conversion schematic diagram of the present utility model.
Fig. 4 is that the utility model adopts direction finding that the track synoptic diagram of microwave detector is installed.
Fig. 5 is a hardware circuit principle block diagram of the present utility model.
Fig. 6 workflow diagram of the present utility model.
Fig. 7 is that the utility model adopts side direction that the installation site synoptic diagram of microwave detector is installed.
Embodiment
The utility model microwave traffic detector system is formed: microwave traffic detecting device mainly partly is made up of microwave part, signal processing, control transmission part and main control computer etc.By the road pavement launched microwave, receive the echoed signal that object reflects simultaneously, again through the pre-service of signal promptly being amplified, obtains containing after the filtering information of information of vehicles frequency band, carry out the conversion of modulus through A/D, by the numerical information analyzing and processing computing of being correlated with of digital signal processor after to its conversion, result after the processing is sent to the Control on Communication part by the interface of inside again, and final and computing machine communicates.(as shown in Figure 5) block diagram work-based logic: control by DSP, by the D/A conversion of signals, control road pavement launched microwave signal, receive the signal that object reflects simultaneously, amplify through filtering again return signal, obtain containing the information of information of vehicles frequency band after the filtering, carry out the conversion of modulus through A/D, the analyzing and processing computing that digital signal after the conversion is correlated with to its information by dsp processor, result after the processing passes through the logical transition circuit CLPD of DSP again, and connect the HPI oral instructions and deliver to the interface control section, the data after handling are the most at last given computing machine and are shown and issue.Wherein FLASH and RAM are as the peripheral storage of digital processing part.
System architecture comprises:
1) microwave part: mainly realize the emission and the acceptance of microwave signal;
2) microwave amplification filtering circuit part and VCO (voltage-controlled concussion) drive to regulate: mainly finish the adjusting of microwave signal emission and the signal of the microwave signal that reflects is amplified and filtering; Regulate the dc offset voltage of this triangular signal and peak value, valley point voltage value, make it to meet the requirement of centre frequency and frequency deviation.
3) FLASH: numeral is dodged very little, mainly stores the driver of dsp processor;
4) RAM: physical memory, mainly store DSP and handle required parameter information;
5) D/A: major function is to convert digital signal to simulating signal;
6) A/D: major function is to convert the microwave mode analog signal to accessible digital signal;
7) DSP: digital processing unit also is hardware digital processing and core CPU, mainly finishes the Treatment Analysis to microwave signal, and obtains detecting result.After the A/D data converted is stored through data buffering, send into to be equipped with these digital signals are carried out the real-time FFT conversion, obtain comprising the information of dynamic vehicle, the spectrum signature of the information of static target and noise, determine the threshold value of signal spectrum then again according to actual conditions, filter static target and noise signal, go out the flow of vehicle simultaneously in conjunction with the lobe calculation of parameter of launched microwave according to difference signal characteristic constantly, vehicle, the dsp chip of average velocity and lane occupancy ratio parameter process software is sent the above-mentioned parameter data into the corresponding interface place by the output terminal of dsp chip again.
8) CPLD: logical transition circuit;
9) control and hop: the signal after main realization will be handled is transferred to host computer;
10) main control computer: the signal after main realization is handled shows and issue.
The microwave part: in the process that realizes the Microwave Measurement function, topmost application is the principle of tellurometer survey.(1) measures distance, will demonstrate definite track.(2) measure distance, draw the concrete time will calculate speed.(3) measure distance, can draw coarse vehicle commander, can determine vehicle with this through further calculating.Concrete principle of work is described as follows with reference to Fig. 1:
Antenna is launched the microwave that frequency is F1 constantly at T1, and through the reflection of automobile, the ripple of F1 is reflected and is received by antenna, and frequency does not change.This moment, antenna was the ripple of F2 in transmission frequency, because the variation of frequency is linear, so can know that the moment of this moment is T2; Promptly derive Δ t by Δ f, the transfer rate of microwave is known, just can calculate the distance of car and antenna.According to distance, can mark off the track easily.
At the forward measuring distance and then when calculating speed, consider the influence of Doppler shift to measuring distance.The phenomenon that the wave frequency that with respect to the motion of propagation medium the observer is received because of wave source or observer changes is Doppler effect.
Moving the Doppler frequency that produces is:
f
a＝cosθ(v/λ)
In the formula, v is a moving body speed, and λ is an operation wavelength, and θ is the microwave incident angle
What can be similar to calculates, because the frequency difference scopes that produce during 100 kilometers/hour operations of Doppler effect automobile, so by measuring frequency-splitting, calculate in the method for distance, the influence of Doppler effect be can not ignore.
When adopting the triangular wave swept-frequency signal (seeing shown in Figure 2), just can eliminate the influence of Doppler effect by the Fourier transform of return path signal.Fig. 3 has shown utilization FFT conversion, can find the solution the frequency-splitting f ' that f=|F2-F1| and Doppler effect produce out respectively, and (one) obtains frequency with distance dependent by linear transformation; (2) pass through about twice conversion, carry out the difference computing again and can calculate f '; Two kinds of methods can solve speed, consider the comfort level of dealing with problems, and generally all adopt the method for ().
Choosing of swept-frequency signal:
The slope of swept-frequency signal can not be too high, and when slope was too high, the condition of time and frequency can not reach simultaneously; When slope was too low, resolution did not reach requirement.
1), the time---need consider fuzzy problem.That is to say that near the detected value the triangular wave turning point blurs.Probably be the launched microwave T1 moment, frequency F1 is in the rising edge of frequency; And receiving the moment T2 of frequency, frequency F2 has been in the negative edge of frequency.Can not correctly obtain the difference of time like this by the difference of frequency, have very mistake, be called the confusion region.Detected numerical value need be filtered out in the confusion region.That is to say, be removing a confusion region time period Δ t1. about the triangular wave turning point respectively
2), the time---need to consider the omission problem.Owing to considered fuzzy problem, in time fuzzy section is omitted, but the omission phenomenon might take place, in 2 Δ t1 times, vehicle has passed through test specification, is called omission.The time that the condition of avoiding is a vehicle by test specification will be far longer than 2 Δ t1.Be Δ t2＞＞2 Δ t1; Δ t2=1
Min/ v
Max1
MinGet common vehicle commander, v
MaxBe the max speed.
3), time---turning point problem.Because the triangular wave that circuit produces can not be linear fully near head and the tail, so non-linear time period Δ t3＜Δ t1.
4), frequency---centre frequency stuck-at-0.525GH
zFrequency and time are linear distribution.Above analysis has all obtained confirmation in about the correlation test of RTMS, can obtain data from experiment.The T=640 microsecond; Δ t1=0.53 microsecond; Δ t2=36 millisecond; F
Max-F
Min=60Mhz
Utilization DSP carries out the FFT computing:
The FFT conversion is exactly at set intervals time-domain signal to be sampled, and the data of these samplings is sent into dsp chip iterate computing, thereby obtain the signal of frequency domain.
Detecting in the microwave traffic needs to carry out to the received signal 1024 FFT conversion in this cover system, come the analytic signal feature from frequency domain characteristic, distinguish by measure such as filtering and then with the vehicle on the different tracks on the road again, finally obtain the car statistics data that we need.
The VCO voltage controlled oscillator:
This is the major part of microwave source, and VCO comes down to a voltage-frequency translation circuit, also just controls the variation of oscillation frequency by the variation of voltage.Its oscillation frequency f
0(t) with control voltage V
c(t) relation between can be expressed as:
f
0(t)＝K
0V
c(t)
K wherein
0Be proportionality constant, be called the voltage-controlled sensitivity of VCO (VCO), unit is Hz/V.We utilize it to produce chirped microwave sounding signal.
Determining of vehicle resolution:
Vehicle resolution is meant that the microwave detector of side direction installation on the direction that microwave covers (as shown in Figure 4), can detect the minimum widith of vehicle.
System has been mentioned to the resulting frequency-splitting difference of the vehicle on the different distance in the front, the bandwidth of the triangular wave rise time section swept-frequency signal institute modulation signal that utilize to produce and the distance that microwave is during this period of time propagated can obtain the difference frequency signal of different tracks vehicle correspondence, in conjunction with dsp processor this difference frequency signal is carried out FFT conversion (the triangular wave time period of sampling), can obtain the vehicle resolution parameter of system.
Modulation signal (2 triangular waves) time T=2.4ms, (or decline) section that rises time t=0.6ms, modulation band-width M=60Mhz, microwave propagation speed v (being approximately the light velocity) is apart from the pairing frequency f of object of 1 meter of microwave detector
1, carry out the minimum frequency value f that the FFT conversion can be differentiated in the 2.4ms
2By
M/vt＝f
1/2
f
1＝666Hz
f
2＝1/T＝417Hz
Software system design:
In the process of Design of System Software, can be divided into three parts.
1, DSP data analysis and processing
Harvard (Havard) structure that dsp chip inside has adopted the program space and data space to separate, allow instruction fetch simultaneously and fetch operand, and adopted the course of work of multiple bus architecture and streamline, thereby improve the travelling speed of DSP greatly, can guarantee that also multiplication accumulating operation with the most use in the digital signal processing can finish in the single instruction cycle.According to the good characteristic of DSP, to plan to select the TMS320C54x chip for use, its travelling speed can reach 100MIPS, can carry out FFT computing fast.
Divide two stages in the process that DSP analyzes and handles:
One, tests on the Target Board
Can also handle many ground unrests (signal that is returned by stationary body that promptly proposes in the middle of principle analysis) in to the Signal Processing process at DSP, be useful signal so what will be distinguished, and what is the ground unrest garbage signal.So on Target Board, test to extract signal characteristic, further formulate signal extraction and background and distinguish the scheme of eliminating.
Two, programming
After the A/D data converted is stored through data buffering, send into dsp chip, adopt dma mode, to the data-moving in the data buffer zone to the DSP data storage area, the TMS320C54x chip carries out 1024 real-time FFT conversion to these digital signals, obtain the spectrum signature of signal, these frequency spectrums comprise the information of dynamic vehicle, the information that static target and noise are also arranged, determine the threshold value of signal spectrum then according to actual conditions again, reach the purpose that filters static target and noise signal, guarantee the corresponding accuracy that has or not the vehicle process of judging constantly.Simultaneously go out the speed of vehicle in conjunction with the lobe calculation of parameter of launched microwave according to difference signal characteristic constantly, the time distance, analyze vehicle.At last these data are sent into the corresponding interface place.Above flow process is referring to Fig. 6.
The interface module design:
In the middle of the interface module design, tentatively be chosen to be the RS232 serial line interface.The RS232 interface is relatively stable, and technology is comparative maturity also, function expansion and applying mechanically after being convenient to.
The PC monitoring software:
The PC monitoring software receives the information send over, carries out information format conversion and some simple calculations.Design of software will lean on the content of the final data of exporting of DSP and the size of quantity of information to determine.Smaller when the quantity of information of DSP output, when the signal that is to say input DSP did not carry out a series of processing, the requirement of the system software in the computing machine and design will more complicated, because will further analyze its signal; On the contrary, if the quantity of information of DSP output is very big, system software just carries out the demonstration directly perceived at interface to the data that pass to PC in the computing machine so.The software design of this part will rely on the performance level of DSP part thus.
The system applies mode:
Need the number of track-lines of detection and the position relation of column to see shown in Figure 7.In order to reduce the generation that large car blocks situation fully, this device setting height(from bottom) height of should trying one's best is such as being above the ground level 5 meters.This Unit Installation column must be arranged on outside first detecting area, rearmounted distance (rearmounted distance, a nearest exactly distance that needs the track of detection) wants to guarantee that the projection of wave beam can cover the track that all need detect, guarantee projection simultaneously and detect the road quadrature.Select suitable setting height(from bottom) and select rational rearmounted distance according to the number of track-lines that the MTD needs detect, can guarantee better to receive the reflected signal of vehicular sideview.Correct mode should meet the following formula of parameter shown in Figure 7:
L+L1/H＝Ctg(θ-α/2)
L1/H＝Ctg(θ-α/2)
The normative reference that the postposition distance of column and setting height(from bottom) are provided with, when rearmounted distance during greater than 6 meters, the column height can suitably increase.When detecting number of track-lines (bar) 2-3, L1 is rearmounted apart from (rice) 3.5～4.0, and H suggestion setting height(from bottom) is not less than (rice) 5; When detecting number of track-lines (bar) 4, L1 is rearmounted apart from (rice) 4.0～4.5, and H suggestion setting height(from bottom) is not less than (rice) 5.5; When detecting number of track-lines (bar) 6, L1 is rearmounted apart from (rice) 4.5～5.0, and H suggestion setting height(from bottom) is not less than (rice) 5.5; When detecting number of track-lines (bar) 8, L1 is rearmounted apart from (rice) 5.0～7.0, and H suggestion setting height(from bottom) is not less than (rice) 6.
Claims (3)
1, a kind of microwave vehicular traffic information detector is characterized in that its structure comprises:
The microwave part: mainly signal circuit and microwave antenna three parts that reflected by the chirped microwave signal circuit of emission, reception are formed, wherein the direction setting of microwave antenna can cover the track that all need detect with the projection that guarantees wave beam, guarantees projection simultaneously and detects the road quadrature; The microwave signal circuit part that makes antenna launch chirped triangular signal is connected with the output terminal of the voltage-frequency translation circuit that produces voltage-controlled concussion driving adjusting triangular signal, and is driven by it; The output terminal of the signal circuit section that reception reflects behind detection, mixting circuit, connects the input end of digital circuit part;
The digital circuit processing section: the A/D data converted is sent into dsp chip through after the data buffering storage, and the data that will calculate flow, vehicle, average velocity and the lane occupancy ratio parameter of vehicle by the output terminal of dsp chip are sent into the corresponding interface place again.
2, a kind of microwave vehicular traffic information detector as claimed in claim 1, it is characterized in that: it is chirped control circuit structure that microwave transmits and receives, obtain information of vehicles via dsp processor and the processing of interrelated logic device, and this information of vehicles is sent to the circuit of control interface.
3, a kind of microwave vehicular traffic information detector as claimed in claim 1, it is characterized in that: the peripheral circuit of described dsp processor mainly comprises the digital flash memories of the driver that stores dsp processor and mainly stores the hardware logic structures such as physical memory device RAM of dsp processor desired parameters information.
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| CN 200620113150 CN2929859Y (en) | 2006-04-26 | 2006-04-26 | Microwave traffic vehicle information detector |
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|---|---|---|---|
| CN 200620113150 CN2929859Y (en) | 2006-04-26 | 2006-04-26 | Microwave traffic vehicle information detector |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101968927A (en) * | 2010-09-21 | 2011-02-09 | 隋亚刚 | Detection system for acquiring traffic flow by using high-definition video and microwave detection selectively |
| CN102214396A (en) * | 2010-04-09 | 2011-10-12 | 罗仁泽 | Intelligent traffic system based on microwave detection |
| CN104484998A (en) * | 2014-12-25 | 2015-04-01 | 北京万集科技股份有限公司 | Vehicle detection device and vehicle anti-tracking method |
| CN105046960A (en) * | 2015-07-10 | 2015-11-11 | 潘进 | Method and apparatus for analyzing road congestion state and detecting illegal parking |
| CN108020838A (en) * | 2016-11-02 | 2018-05-11 | 惠州市德赛西威汽车电子股份有限公司 | A kind of processing method of MMW RADAR SIGNAL USING in adaptive cruise |
-
2006
- 2006-04-26 CN CN 200620113150 patent/CN2929859Y/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102214396A (en) * | 2010-04-09 | 2011-10-12 | 罗仁泽 | Intelligent traffic system based on microwave detection |
| CN101968927A (en) * | 2010-09-21 | 2011-02-09 | 隋亚刚 | Detection system for acquiring traffic flow by using high-definition video and microwave detection selectively |
| CN101968927B (en) * | 2010-09-21 | 2015-07-01 | 隋亚刚 | Detection system for acquiring traffic flow by using high-definition video and microwave detection selectively |
| CN104484998A (en) * | 2014-12-25 | 2015-04-01 | 北京万集科技股份有限公司 | Vehicle detection device and vehicle anti-tracking method |
| CN105046960A (en) * | 2015-07-10 | 2015-11-11 | 潘进 | Method and apparatus for analyzing road congestion state and detecting illegal parking |
| CN105046960B (en) * | 2015-07-10 | 2018-03-02 | 武汉微智创大科技有限公司 | A kind of method and device detected to congestion in road state analysis and illegal parking |
| CN108020838A (en) * | 2016-11-02 | 2018-05-11 | 惠州市德赛西威汽车电子股份有限公司 | A kind of processing method of MMW RADAR SIGNAL USING in adaptive cruise |
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Granted publication date: 20070801 |
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