CN102401899A - High-precision millimeter wave automobile radar - Google Patents

Abstract

A high-precision millimeter wave automobile radar is an active radar device (see attached figures). An automobile with the radar has a self-positioning function, and can actively and continuously broadcast self location via legal 75GHz-76GHz millimeter wave bands or 24GHz-26GHz short-distance radar wave bands. Accordingly, each automobile can obtain information of locations and speeds of all automobiles within about 200 meters around the automobile, and traffic collision is prevented quite precisely.

Description

The millimeter-wave automotive radar of pinpoint accuracy

Technical field

The invention belongs to vehicle radar system

Background technology

Car radar be a kind of be the short distance ground radar of purpose to reduce the automobile traffic accident, its operating distance is about 200 meters, resolution is 0.2 meter to 1 meter scope.

Traditional car radar is the same with general radar, sends electromagnetic field signal by radar system to target, and this signal reflects on the surface of target, and the positional information that obtains target is handled and analyzed to radar system through the reception to reflected signal.

The electromagnetic field signal of car radar emission has two kinds of patterns basically, and what early stage car radar was used is pulse signal, and what generally use now is cline frequency modulation (CWFM)

1.1 the principle of work of the car radar of pulse signal type is the same with general radar, from time interval of measuring transponder pulse and reflected impulse range-to-go.Fig. 1 is its principle schematic, and t0 is a transponder pulse, and t1 is a reflected impulse, and t1 is t for the time delay of t0 _dTarget can be apart from d from t _dIn calculate and get

$d=\frac{V_{\mathrm{em}}{t}_d}{2}---\left(1\right)$

V _CmBe the aerial speed of electromagnetic wave

1.2 the ultimate principle of the car radar of cline frequency modulation type is that the modulating frequency in the radar emission signal is that the linear function of time is as shown in Figure 2.

F _me＝f ₀+Kt (2)

K is a frequency change rate

From the return modulating frequency f of signal of target reflection _MbWith respect to the modulating frequency that transmits a temporal delay t is arranged _d, as shown in Figure 3.At the moment of a certain appointment, f _MbAnd f _MeDifference on the frequency be Δ f it be the function of target range, target range d can calculate and get from Δ f

$d=\frac{(\mathrm{\Δf}\×V_{\mathrm{em}})}{2k}---\left(3\right)$

The problem of orthodox car radar

1) when there is bend in the place ahead of running car road, traditional car radar can be the other house of road, and erroneous judgement such as trees is as shown in Figure 4 for front vehicles.

2) when running car during at descending, traditional car radar can be as shown in Figure 5 for front vehicles the erroneous judgement of the ground of road ahead.

3) automobile is the mobile object of group, on a road, has the volume automobile and is going, particularly on the highway of multilane.Generally need to install three radars, the place ahead and both sides on each automobile.The car radar of being equipped on each automobile like this might interfere with each other.

In traditional car radar, target always under the irradiation of transmitter millimeter wave wave beam, produces reflected signal, and target is the positional information that it is provided passively.The problem of this system in second joint, mention, also have one to be exactly dependence for the size and the target surface reflection characteristic of target, caused the sensitivity of system, reliability has sizable uncertainty

This patent has proposed the system of a brand-new car radar: active millimeter-wave automotive radar.

Description of drawings

To with the mode of example the present invention be described with reference to accompanying drawing now, wherein:

Fig. 1 is the sequential chart of traditional pulse car radar

Fig. 2 is the frequency-time chart of the car radar of traditional cline frequency modulation type

Fig. 3 is the frequency difference figure with reflected signal of transmitting of the car radar of traditional cline frequency modulation type

Fig. 4 is the erroneous judgement synoptic diagram of orthodox car radar when bend

Fig. 5 is the erroneous judgement synoptic diagram of orthodox car radar when descending

Fig. 6 is the system diagram of car radar of the present invention

Fig. 7 is the structural drawing of a cover car radar device of the present invention.

Summary of the invention

This patent has proposed initiatively to provide self-position information to be the basis with target, is the brand-new system of the active millimeter-wave automotive radar of communications platform with legal car radar millimere-wave band (75GHz is to 76GHz).

The block diagram of this system is as shown in Figure 6

Embodiment

The principle of work of active car radar is that it has the function of location, and constantly carries peripherad automobile through the millimeter wave neck section of car radar and issue the position data of oneself, the position data separately that automobile is sent around receiving simultaneously.The recording controller device of every active car radar can be formed a dynamic data base to these data like this, by the distance that can calculate this automobile and automobile on every side in the position data and be shown as a width of cloth with this automobile be the center around position and speed figure (the following abbreviation position speed figure of automobile.This automobile position can be represented with blueness among the speed figure on the throne, and the position of each automobile can represent with different colours that to the possible effect of this automotive safety driving as representing to have the greatest impact with peony, pink is taken second place according to this automobile on every side, or the like.Because position data is upgraded constantly, can calculate the speed of this automobile and on every side automobile for the relative velocity of this automobile.Above data add the brake distance of getting on the car, and can set the measure of various warnings and reaction, thereby guarantee traffic safety, particularly help the safe driving under the very low situation of visibility.

System architecture

The structure that the every cover car radar 101 of one cover car radar (101) all is housed on each automobile is shown in figure seven.It is by steady arm 102, controller 103, and register 104, millimeter wave transmitter 105, millimeter wave receiver 106, display alarm device 107 is formed.

1) steady arm 102

Steady arm can be GPS (GPS) or the Big Dipper positioning system or gyroscope positioning system, but is not limited to said system, as long as any system of ground positioning function is arranged and have resolution to be lower than 1 meter the steady arm that all can be used as this patent.Steady arm is constantly measured the position of this automobile, and delivers to controller 103 to this position data

2). controller 103

Microprocessor of controller, it has following function:

< 1>this automobile position information of sending steady arm here is delivered to millimeter wave transmitter 105.

< 2>the automobile position data of sending millimeter wave receiver 106 here are on every side calculated and are handled

< 3>calculate this car speed

< 4>calculate around each automobile with respect to the distance of this automobile

< 5>calculate around each automobile with respect to the speed of this automobile

< 6 >. form a dynamic data base to the data of aforementioned calculation gained and leave in the register 104

< 7 >. the position speed of automobile is schemed around producing, and is shown to this driver through the display alarm device

< 8>have too highly when possible when this car speed, advise for driver's acousto-optic reduction of speed through 107.

< 9>when the automobile distance in this automobile and the place ahead less than brake apart from the time, give the alarm of driver's acousto-optic reduction of speed through 107

< 10>when this automobile changes the track,, give driver's audible and visual alarm through 107 like the car collision on the possible and new track

< 11>automatic whistling warning the other side driver when automobile might knock this automobile on every side.

3) register 104

Register is nonvolatile, under powering-off state, also can preserve data, and it is the depository of dynamic data base and position speed figure, and it can preserve the data in up-to-date a few minutes.Just in case there is traffic accident to take place, its data will be to judge the strong evidence of responsibility.

4). millimeter wave transmitter 105

The millimeter wave transmitter is a carrier frequency in the short range transmitter of 75G to 76G, it constantly slave controller obtain the position data of this automobile, and launch car radar towards periphery to them.Its communication distance can guarantee the privacy of personal automobile like this at hundreds of rice (normally 200 meters to 300 meters).

5). millimeter wave receiver 106

The millimeter wave receiver is a carrier frequency at the short distance receiver of 75G to 76G, and it constantly receives the position data of each automobile that car radar on every side sends.And deliver to controller 103 to them, the same its communication distance with transmitter can guarantee the privacy of personal automobile like this at hundreds of rice (normally 200 meters to 300 meters).

6). display alarm device 107

It is the peripherals of controller 103, and it can show position speed figure and send various sound and alarm signal light.

System advantage

The inexactness of traditional radar of 1) having avoided up hill and dale in second joint, describing, because the street, house etc. can not send the position signalling of microwave.

2) share a communications platform and do not have interference.

3) wavelength of millimeter wave is greater than light wave, and it is less influenced by the visibility of weather, can be under the lower situation of visibility guarantee driving safety

4) can obtain the fast information in position of each automobile in 200 to 300 meters, take place to notify automobile on every side immediately, prevent that the crowd from hitting incident if any traffic accident.

Claims (1)

1. active vehicle radar system, it is made up of following part:

(1) steady arm: it can confirm the position of this automobile in real time

(2) high frequency radio transmitter: it can be the millimeter wqve radio transmitter, but is not limited to the millimeter wave wireless launcher.Its function is the position of constantly issuing this automobile in real time.

(3) high frequency radio receiver: it can be the millimeter wqve radio receiver, but is not limited to the millimeter wqve radio receiver.Its function is constantly to receive the positional information of automobile on every side in real time.

(4) controller: it can be a microprocessor, but is not limited to microprocessor.Its function be this automobile position information that steady arm measures deliver to the high frequency radio transmitter in the issue.It is the position and speed data with reference to each automobile around the center to the position information process Cheng Yiben automobile of automobile around receiving from high frequency wireless receiver; And send various alarm signals according to real-time condition; Can force this vehicle deceleration in case of necessity, brake etc. are to avoid the generation of traffic accident.

(5) alarm device: its function is an automobile alarm signal that sound or light around the driver of this automobile and the danger that might cause a traffic accident to this automobile, but does not limit to alarm signal sound or light.

(6) register: it is a kind of nonvolatile memory device, and its function is that to note in the past in the schedule time be position and speed data and alarm signal with reference to each automobile around the center with this automobile.

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