CN102445689A - Speed-measuring radar system with function of distinguishing vehicle direction - Google Patents
Speed-measuring radar system with function of distinguishing vehicle direction Download PDFInfo
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- CN102445689A CN102445689A CN2011103920702A CN201110392070A CN102445689A CN 102445689 A CN102445689 A CN 102445689A CN 2011103920702 A CN2011103920702 A CN 2011103920702A CN 201110392070 A CN201110392070 A CN 201110392070A CN 102445689 A CN102445689 A CN 102445689A
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Abstract
The invention relates to a speed-measuring radar system with a function of distinguishing a vehicle direction, and the system comprises a frequency source, wherein the frequency source is connected to the input end of a branch line coupler; a transceiving antenna is connected to the branch line coupler; the coupling port of the branch line coupler is respectively connected to a first power divider and a second power divider; the first power divider is used for outputting in two paths; one path is connected to a first frequency mixer through a 90-degree delay line; the other path is connected to a second frequency mixer; and the output end of the second power divider is respectively connected to the first and second frequency mixers. The speed-measuring radar system provided by the invention is low in production cost, compact in structure, small in volume, high in stability, excellent in property and reliable in circuit property; compared with other speed-measuring radar systems, the speed-measuring radar system has the characteristics of low cost and high efficiency; and the speed-measuring radar system can be used for detecting the overspeed of a vehicle and can be widely applied to a police snap-shooting speed-measuring system.
Description
Technical field
The present invention relates to a kind of velocity radar system, especially a kind of velocity radar system with direction of traffic discriminant function.
Background technology
Along with the fast development of highway communication, it is unusual severe that the safety problem on the highway becomes, and drives over the speed limit, road accident rate is higher is the main cause that causes traffic hazard.In order to reduce owing to the traffic hazard and the violation phenomenon of driving over the speed limit and causing; Through using velocity radar to detect road speed; Velocity radar is to utilize Doppler effect to measure measuring speed, and its use not only makes the measurement of the speed of a motor vehicle more accurate, and is convenient to police's monitoring of enforcing the law; Detect the also hypervelocity behavior of registration of vehicle, effectively check because the traffic hazard that hypervelocity produces through severe punitive measures.
The defective of existing velocity radar is following: only be operated under the single-mode, accomplish complicated and accurate information acquisition, have higher cost; At the highway velocity radar, when the car operation is arranged on two tracks simultaneously, and in the opposite direction, only can detect overspeed of vehicle, can't differentiate over-speed vehicles, can only abandon capturing for avoiding erroneous judgement, increased hidden peril of accident virtually; Velocity radar receives signal and in receiver, is converted to the process of intermediate frequency from radio frequency, and major part does not have additional treatments, and then the symbol of Doppler shift will lose, and with respect to the direction of motion of target (near or away from) can can't confirm; Since the volume-diminished of degree of testing the speed radar antenna, most of flat plane antenna of printing that adopts, little, the light weight of its profile, but its radiation efficiency is low, power attenuation is serious because its serious conductor losses causes.
Summary of the invention
The object of the present invention is to provide a kind of high-performance, low cost, easy to use, the velocity radar system that can distinguish direction of traffic with direction of traffic discriminant function.
For realizing above-mentioned purpose; The present invention has adopted following technical scheme: a kind of velocity radar system with direction of traffic discriminant function, comprise frequency source, and frequency source links to each other with the input end of branch line coupler; Connect dual-mode antenna on the branch line coupler; The coupling aperture of branch line coupler links to each other with first and second power splitter respectively, and first power splitter divides two-way output, and the 90 ° of lag lines of leading up to link to each other with first frequency mixer; Another road links to each other with second frequency mixer, and the output terminal of second power splitter links to each other with first and second frequency mixer respectively.
Can know by technique scheme; First power splitter among the present invention is divided into two-way to the frequency source signal; Wherein through the frequency source of 90 ° of lag lines 90 ° of phase places of signal change; Second power splitter is divided into two-way with echoed signal, pass through first and second frequency mixer mixing again after, can produce the I/Q orthogonal signal that are used to differentiate car speed and travel direction.Production cost of the present invention is low, compact conformation, volume is little, degree of stability is high, function admirable; And circuit performance is reliable; With respect to other velocity radar system, have more low cost, dynamical characteristics; Owing to can effectively detect overspeed of vehicle, can be widely used in alert with capturing velocity-measuring system.
Description of drawings
Fig. 1 is a circuit block diagram of the present invention.
Embodiment
A kind of velocity radar system with direction of traffic discriminant function comprises frequency source 1, and frequency source 1 links to each other with the input end of branch line coupler 3; Connect dual-mode antenna 4 on the branch line coupler 3; The coupling aperture of branch line coupler 3 links to each other with first and second power splitter 5,6 respectively, the two-way output in 5 fens of first power splitter, and the 90 ° of lag lines 7 of leading up to link to each other with first frequency mixer 8; Another road links to each other with second frequency mixer 9, and the output terminal of second power splitter 6 links to each other with first and second frequency mixer 8,9 respectively.The output terminal of described first frequency mixer 8 links to each other with the input end of first low-pass filter 12, and the output terminal of second frequency mixer 9 links to each other with the input end of second low-pass filter 13, and is as shown in Figure 1.
As shown in Figure 1, the output terminal of described frequency source 1 links to each other with the input end of isolator 2, and the output terminal of isolator 2 links to each other with the input end of branch line coupler 3.In order to make frequency source 1 and branch line coupler 3 Circuit Matching; The isolator 2 that adds a low insertion loss at the output terminal of frequency source 1; Utilize the one-way transmission character of isolator 2, signal only can will be absorbed by isolator 2 signal that reflects single direction transmission; Prevent that mainly the microwave signal of launching from reflecting, and improve the frequency stability of oscillator.Described frequency source 1 adopts Gunn diode oscillator, and this oscillator frequency stabilizing degree is good, and phase noise is low, and temperature stability is than higher.
As shown in Figure 1, branch line coupler 3 adopts the high integration microstrip circuit, is convenient to adjustment, and isolation performance is good, has than higher safety coefficient and reliability, and small product size is little, in light weight, portable.Dual-mode antenna 4 is used to receive signal and transmits, and dual-mode antenna 4 adopts the waveguide conical-horn antenna, and not only loss is little, radiation efficiency is high, light weight, and is convenient to processing, reduces complicated debug process.First and second frequency mixer 8,9 adopts the balanced type frequency mixer; The balanced type frequency mixer is greatly improved the isolation of each port because balanced bridge is arranged, and reduces local oscillator and introduces the mid-frequency noise that AM noise produced; The input loss of signal reduces; Circuit is compact conformation not only, and the processing volume is little, in light weight.Described first and second low-pass filter 12,13 adopts active low-pass filter.
As shown in Figure 1; Described first frequency mixer 8 is made up of first electric bridge 10, diode D1, D2; The input end of first electric bridge 10 links to each other with the output terminal of 90 ° of lag lines 7, second power splitter 6 respectively; The output terminal of first electric bridge 10 links to each other with the negative electrode of diode D1, the anode of diode D2 respectively, links to each other with the input end of first low-pass filter 12 after the negative electrode parallel connection of the anode of diode D1, diode D2; Described second frequency mixer 9 is made up of second electric bridge 11, diode D3, D4; The input end of second electric bridge 11 links to each other with the output terminal of first and second power splitter respectively; The output terminal of second electric bridge 11 links to each other with the negative electrode of diode D3, the anode of diode D4 respectively, links to each other with the input end of second low-pass filter 13 after the negative electrode parallel connection of the anode of diode D3, diode D4.Electric bridge can carry out good isolation to oscillator and echoed signal, and circuit level is high, cost is low.
Below in conjunction with Fig. 1 the present invention is further described.
Frequency source 1 produces oscillation frequency, through branch line coupler 3 couplings, the signal of being gone out by dual-mode antenna 4 directed radiations on the one hand; Propagate with the electromagnetic wave form in the space, when this electromagnetic wave runs into vehicle in the space, reflect, if vehicle moves; The wave frequency that then reflects has added a Doppler frequency that is directly proportional with vehicle movement speed, and this echo is received by dual-mode antenna 4, through branch line coupler 3; Send to second power splitter 6; Second power splitter, 6 output two-way echoed signals, one tunnel echoed signal is carried out mixing in first frequency mixer 8, and another road echoed signal is carried out mixing in second frequency mixer 9; Frequency source 1 produces oscillator signal; Through branch line coupler 3 couplings, directly get into the two-way output in 5 fens of first power splitter, 5, the first power splitters; One road oscillator signal gets into 8 mixing of first frequency mixer through 90 ° of lag lines, 7 backs, and another road oscillator signal directly gets into 9 mixing of second frequency mixer; First and second frequency mixer 8,9 is through producing I/Q quadrature intermediate-freuqncy signal after the mixing; Carry out filtering through first and second low-pass filter 12,13 respectively; The signal of exporting after the filtering supplies back level signal Processing to use, and the direction and the speed of vehicle operating can be provided on display screen.
The oscillator signal mixing mutually of the echoed signal that dual-mode antenna 4 receives and frequency source 1 generation utilizes the non-linear generation medium frequency signal of diode, so that make things convenient for next step signal Processing.First and second electric bridge 10,11 has the effect of impedance conversion; Under desirable matching condition, received signal power and frequency source power all are added on two diodes through first and second electric bridge, and the phase noise of frequency source 1 can be offset in two tube currents; Also offset simultaneously a part of combination harmonic component; Both improve mixing purity, improved conversion loss again, thereby the AM noise in blanketing frequency source 1 and the noise of even-order harmonic effectively.Simultaneously, can make the noise cancellation of frequency source 1, thereby noiseproof feature improves by means of first and second electric bridge 10,11; And first and second electric bridge 10,11 makes again to receive between signal and the oscillator and reaches good, and each interport isolation is greatly improved, and it is more intense that clutter is suppressed ability.Frequency source 1 is in order to produce the two-way orthogonal signal through 90 ° of lag lines 7.
In order to reduce electromagnetic radiation and EM coupling; First and second frequency mixer 8,9 all is closed with a metal enclosed cavity, and described first and second frequency mixer 8,9 is two frequency mixer that structure is identical, adopts the microstrip circuit design; Volume is little, in light weight, reliability is high, and cost of manufacture is low; The employing of first and second electric bridge 10,11 simultaneously makes again between frequency source 1 and the echoed signal good isolation has been arranged, and the I/Q orthogonal signal of generation can provide the direction and the speed of vehicle operating.
Described first power splitter 5 is divided into two-way to the oscillator signal of frequency source 1 output, and second power splitter 6 is to be divided into two-way to echoed signal.The power splitter Insertion Loss is little, phase equalization and amplitude balance property are good, to guarantee to have higher distribution; The isolation performance of two branch roads is good, has than higher safety coefficient and reliability; Circuit form is simple, be convenient to adjustment, and volume is little, and the miniaturization of equipment and integrated is convenient in convenient processing.
If it is the oscillator signal of 35.1GHz that frequency source 1 produces frequency, be transferred to branch line coupler 3 through isolator 2, branch line coupler 3 is divided into two-way, and one the road carries out radiation, one road to first power splitter 5 to dual-mode antenna 4.The frequency of echoed signal that the signal of emission is run into the vehicle reflection of motion is 35.1GHz+fd, and echoed signal gets into second power splitter 6 through branch line coupler 3.The frequency that one road frequency source 1 produces is that the oscillator signal of 35.1GHz carries out mixing through 90 ° of lag lines 7 and echoed signal, and producing one tunnel frequency is the signal of fd1; The frequency that another road frequency source 1 produces is the direct and echoed signal mixing of oscillator signal of 35.1GHz; Producing frequency is the signal of fd2; Fd1 is identical with the fd2 amplitude, and just the phase phasic difference is 90 °, the I that produces and first and second low-pass filter 12,13 filtering of Q signal process; Supply the back level to handle, so that calculate the direction and the speed of vehicle movement.
In sum; First power splitter 5 among the present invention is divided into two-way to the frequency source signal; Wherein through the frequency source signal change of 90 ° of lag lines 7 after 90 ° of phase places, simultaneously, second power splitter 6 is divided into two-way with echoed signal; After passing through first and second frequency mixer 8,9 mixing again, can produce the I/Q orthogonal signal that are used to differentiate car speed and travel direction.Production cost of the present invention is low, compact conformation, volume is little, degree of stability is high, function admirable; And circuit performance is reliable; With respect to other velocity radar system, have more low cost, dynamical characteristics; Owing to can effectively detect overspeed of vehicle, can be widely used in alert with capturing velocity-measuring system.
Claims (6)
1. velocity radar system with direction of traffic discriminant function; It is characterized in that: comprise frequency source (1); Frequency source (1) links to each other with the input end of branch line coupler (3), and branch line coupler (3) is gone up and connected dual-mode antenna (4), and the coupling aperture of branch line coupler (3) links to each other with first and second power splitter (5,6) respectively; First power splitter (5) divides two-way output; The 90 ° of lag lines (7) of leading up to link to each other with first frequency mixer (8), and another road links to each other with second frequency mixer (9), and the output terminal of second power splitter (6) links to each other with first and second frequency mixer (8,9) respectively.
2. the velocity radar system with direction of traffic discriminant function according to claim 1; It is characterized in that: the output terminal of described frequency source (1) links to each other with the input end of isolator (2), and the output terminal of isolator (2) links to each other with the input end of branch line coupler (3).
3. the velocity radar system with direction of traffic discriminant function according to claim 1; It is characterized in that: the output terminal of described first frequency mixer (8) links to each other with the input end of first low-pass filter (12), and the output terminal of second frequency mixer (9) links to each other with the input end of second low-pass filter (13).
4. the velocity radar system with direction of traffic discriminant function according to claim 1; It is characterized in that: described frequency source (1) adopts Gunn diode oscillator; Branch line coupler (3) adopts the high integration microstrip circuit; Dual-mode antenna (4) adopts the waveguide conical-horn antenna, and first and second frequency mixer (8,9) adopts the balanced type frequency mixer.
5. the velocity radar system with direction of traffic discriminant function according to claim 3; It is characterized in that: described first frequency mixer (8) is made up of first electric bridge (10), diode D1, D2; The input end of first electric bridge (10) links to each other with the output terminal of 90 ° of lag lines (7), second power splitter (6) respectively; The output terminal of first electric bridge (10) links to each other with the negative electrode of diode D1, the anode of diode D2 respectively, and the input end with first low-pass filter (12) after the negative electrode parallel connection of the anode of diode D1, diode D2 links to each other; Described second frequency mixer (9) is made up of second electric bridge (11), diode D3, D4; The input end of second electric bridge (11) links to each other with the output terminal of first and second power splitter respectively; The output terminal of second electric bridge (11) links to each other with the negative electrode of diode D3, the anode of diode D4 respectively, and the input end with second low-pass filter (13) after the negative electrode parallel connection of the anode of diode D3, diode D4 links to each other.
6. the velocity radar system with direction of traffic discriminant function according to claim 3 is characterized in that: described first and second low-pass filter (12,13) adopts active low-pass filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011103920702A CN102445689A (en) | 2011-12-01 | 2011-12-01 | Speed-measuring radar system with function of distinguishing vehicle direction |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011103920702A CN102445689A (en) | 2011-12-01 | 2011-12-01 | Speed-measuring radar system with function of distinguishing vehicle direction |
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| CN102445689A true CN102445689A (en) | 2012-05-09 |
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| CN2011103920702A Pending CN102445689A (en) | 2011-12-01 | 2011-12-01 | Speed-measuring radar system with function of distinguishing vehicle direction |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103869305A (en) * | 2014-03-20 | 2014-06-18 | 北京川速微波科技有限公司 | Method for dynamically measuring speed through microwave speed-measuring radar |
| CN104485972A (en) * | 2014-12-16 | 2015-04-01 | 北京华力创通科技股份有限公司 | K-band single antenna transceiver |
| CN104993197A (en) * | 2015-07-13 | 2015-10-21 | 南京理工大学 | UHF waveband outer load power-division balance filter |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU849500A1 (en) * | 1975-07-28 | 1981-07-23 | Предприятие П/Я Г-4149 | Balanced mixer |
| US5557283A (en) * | 1991-08-30 | 1996-09-17 | Sheen; David M. | Real-time wideband holographic surveillance system |
| US20070247352A1 (en) * | 2005-10-05 | 2007-10-25 | Dean Michael | Detecting objects within a near-field of a frequency modulated continuous wave (FMCW) radar system |
| WO2007138812A1 (en) * | 2006-05-30 | 2007-12-06 | Murata Manufacturing Co., Ltd. | Radar device |
| CN202330711U (en) * | 2011-12-01 | 2012-07-11 | 安徽蓝盾光电子股份有限公司 | Speed measuring radar system with vehicle direction identification function |
-
2011
- 2011-12-01 CN CN2011103920702A patent/CN102445689A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU849500A1 (en) * | 1975-07-28 | 1981-07-23 | Предприятие П/Я Г-4149 | Balanced mixer |
| US5557283A (en) * | 1991-08-30 | 1996-09-17 | Sheen; David M. | Real-time wideband holographic surveillance system |
| US20070247352A1 (en) * | 2005-10-05 | 2007-10-25 | Dean Michael | Detecting objects within a near-field of a frequency modulated continuous wave (FMCW) radar system |
| WO2007138812A1 (en) * | 2006-05-30 | 2007-12-06 | Murata Manufacturing Co., Ltd. | Radar device |
| CN202330711U (en) * | 2011-12-01 | 2012-07-11 | 安徽蓝盾光电子股份有限公司 | Speed measuring radar system with vehicle direction identification function |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103869305A (en) * | 2014-03-20 | 2014-06-18 | 北京川速微波科技有限公司 | Method for dynamically measuring speed through microwave speed-measuring radar |
| CN104485972A (en) * | 2014-12-16 | 2015-04-01 | 北京华力创通科技股份有限公司 | K-band single antenna transceiver |
| CN104993197A (en) * | 2015-07-13 | 2015-10-21 | 南京理工大学 | UHF waveband outer load power-division balance filter |
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Application publication date: 20120509 |