CN102508255A - Vehicle-mounted four-wire laser radar system and circuit and method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种车载四线激光雷达系统及其电路、方法，其主要由发射系统、接收系统、光学系统和扫描系统组成。所述发射系统和扫描系统组合在一起，通过直流步进电机控制激光器旋转方式实现雷达扫描，激光器通过水银滑环与外部电路进行电气连接，因此扫描系统体积小。系统依据激光脉冲测距原理，采用4线激光同时扫描，探测距离最大可达200m，分辨率最大可达10cm。因此系统的性能和精确度较高、成本低。结合系统软件可以用来进行车距测量、车速测量、车距保持、碰撞预警、自动巡航、车道偏离预警等功能，辅助驾驶员安全驾驶。

The invention discloses a vehicle-mounted four-line laser radar system and its circuit and method, which are mainly composed of a transmitting system, a receiving system, an optical system and a scanning system. The launch system and the scanning system are combined together, and the laser is controlled by a DC stepping motor to rotate to realize radar scanning, and the laser is electrically connected to an external circuit through a mercury slip ring, so the scanning system is small in size. Based on the principle of laser pulse ranging, the system uses 4 laser lines to scan simultaneously, the maximum detection distance can reach 200m, and the maximum resolution can reach 10cm. Therefore, the performance and accuracy of the system are high and the cost is low. Combined with the system software, it can be used for vehicle distance measurement, vehicle speed measurement, vehicle distance maintenance, collision warning, automatic cruise, lane departure warning and other functions to assist drivers in safe driving.

Description

Vehicle-mounted four line laser radar systems and circuit thereof, method

Technical field

The present invention relates to a kind of application of laser radar, especially relate to a kind of vehicle-mounted laser radar system and application circuit structure and implementation method that 4 laser instruments carry out line sweep simultaneously that have in automobile assistant driving system field.

Background technology

Along with auto industry is flourish, vehicle flowrate constantly increases, and traffic hazard takes place frequently, and driver's burden is also just increasing.In order to reduce the loss that traffic hazard causes, be applied in the middle of the automobile like passive security technology such as air bag, ABS, intelligent headlights, but these passive security measures can only mitigation, the accident that can not prevent takes place.Along with development of electronic technology; Garage widespread use already is various carries out driver assistance like electronic equipments such as navigating instrument, car radars; But when these take place in the accident that prevents, still lean on driver's judgement to carry out, equipment does not have when urgent the authority of control vehicle drive automatically; Emergency case is taking place or driving when absent-minded if the driver has little time to take measures, accident still possibly take place.

Comparatively desirable automobile assistant driving system should have the function such as early warning, lane departure warning of distance survey, front truck vehicle speed measurement, barrier; When collision is taked emergency brake when inevitable automatically and discharged the security function that waits measure protection occupant of air bag in advance; Automatically discern curb, isolation strip and the barrier function of road both sides; The function that in the middle of automatic cruising (ACC), maintains safe distance automatically alleviates driver's burden.The performance of advanced automobile assistant driving system depends mainly on its sensing system and application system.

Car radar is a kind of sensing system in the widespread use of automobile assistant driving system, and it mainly comprises three kinds of ultrasonic radar, microwave radar and laser radars.Wherein ultrasonic radar is effectively found range and is had only several meters, can only use as radar for backing car; The effective range finding microwave radar more farther than ultrasonic radar has that the misty rain of receiving weather effect is little, coverage can reach about 100 meters, but its angle of divergence is too big, and precision is not high when measurement target distance and position, is mainly used in the practical application to test the speed, find range; Laser radar has the measuring accuracy height, and range finding is far away, and characteristics such as excellent performance are applicable to measuring vehicle speed, range finding and target localization.

The advantage of laser radar is that structure is simple relatively, has high monochromaticity, high directivity, the coherence is good, measuring accuracy is higher, detection range is far away, has received widely paying close attention to.Can be applicable to aspects such as automatic cruising (ACC), anti-collision warning, lane departure warning, prospect is boundless.Laser radar mainly is divided into imaging laser radar and non-imaging laser radar, and imaging laser radar is divided into scanning imagery and non-scanning imagery again.But the imaging laser radar three-dimensional imaging is powerful, but technical difficulty is very big, and cost is also very high, and has satisfied not the application demand of the automobile of running at high speed; Non-imaging laser radar has more practical value aspect automotive applications, and it is low to compare its cost of imaging laser radar, and speed is fast, and good stability can also satisfy functional requirement.But a single line sweep laser radar can only be an enterprising line scanning of face, and coverage rate is little, in the middle of the barrier early warning, is easy to cause the disappearance of detection, and can't normally detect barrier going up a slope and be easy to only to detect ground during the vehicle body big rise and fall.And 4 line laser radars can well remedy this shortcoming, have improved the detection degree of accuracy greatly, and becoming different angles scanning also is because this point.1 line laser radar and 4 line laser radar scanning synoptic diagram are as shown in figures 1 and 3.

Summary of the invention

Knack problem of the present invention is: the sensing system excellent properties that how to utilize laser radar; A kind of scanning broad covered area is provided; Can effectively detect target obstacle, and the required laser radar system of automobile assistant driving system that volume is little, cost is low, function is strong.In order to address these problems, the invention provides the technical scheme of following vehicle-mounted four line laser radar systems and circuit and method:

Vehicle-mounted four line laser radar systems mainly are made up of electric power system, control system, emission coefficient, receiving system, optical system and scanning system; Electric power system provides power supply to each system; Control system control emission coefficient is sent laser, and laser is met target object and reflected after handling through optical system; Again after optical system is handled; By receiving system reception reflection echo signal and after carrying out a series of processing, feed back to control system, carry out calculation process by control system; Said emission coefficient is by 4 laser instrument emission laser, and scanning system comprises motor and mercury slip ring, it is characterized in that: said 4 laser instruments are arranged on the motor driving shaft, and receive motor-driven to be rotated scanning, form four line laser radar scannings; Laser instrument is electrically connected through mercury slip ring and external circuit, and the movable end of mercury slip ring is connected with motor driving shaft, rotates with driving shaft with laser instrument.

Further, said 4 laser instruments homeotropic alignment on motor driving shaft becomes row, and its optical axis forms different angles with surface level.During rotation sweep, the scanning coverage rate is wider than a line radar like this.

The present invention is based on the laser pulse ranging principle, the emission coefficient emitted laser burst length is extremely short, the concentration of energy of pulse.Laser pulse ranging and scanning system are organically combined, realized from putting the transformation of line, transformation from single range finding to radar.Adopt the scanning of four line lasers, can be simultaneously four enterprising line scannings of line, the scanning broad covered area prevents the central disappearance that detects of barrier early warning, the scanning effect is as shown in Figure 2.Scanning system realizes scan function through the rotation that dc stepper motor drives semiconductor laser; Adopt the mercury slip ring to connect the laser instrument and the external circuit of high speed rotating; The mercury slip ring is to be a kind of conduction swivel adapter head of fluid media (medium) with mercury; Utilize mercury to carry out electrical signal transfer, replace traditional carbon brush, it is better to be electrically connected performance.The corresponding optical system of emission coefficient and receiving system collimates and shaping to the laser of launching, and makes the angle of divergence of laser enough little, and spot diameter and laser energy transmitance that light beam is formed satisfy request for utilization; And impel more echoed signal to enter into receiving circuit, and prevent the interference of the incoherent light photograph of other wavelength.

A kind of circuit of realizing vehicle-mounted four line laser radar systems comprises control system circuit, emission coefficient circuit, scanning system circuit, receiving system circuit, electric power system circuit; Wherein the electric power system circuit includes the power module to each circuit system power supply; It is characterized in that: said control system circuit comprises control chip and display module that is connected with control chip respectively and communication interface, and the display module displaying contents is controlled by control chip, and control chip is through communication interface and external communication; Said emission coefficient comprises pulse producer, switch driving circuit, the laser instrument that links to each other successively, and pulse producer links to each other with control system circuit control chip, and controlled by it; Pulse producer provides signal drive signal to switch driving circuit, drives 4 laser works by switch driving circuit; Scanning system circuit comprises motor and mercury slip ring, and mercury slip ring stiff end is electrically connected through terminals and driving circuit; Said 4 laser instruments are arranged on the motor driving shaft, by being rotated scanning with motor driving shaft, form four line laser radar scannings with the movable end of mercury ring; Laser instrument is electrically connected through the terminals and the mercury slip ring of mercury slip ring movable end; Said receiving system circuit mainly is made up of the bias circuit that links to each other successively, receiving circuit, amplifying circuit, moment discriminator circuit, time interval measuring circuit; Bias circuit is that receiving circuit provides required bias voltage, and receiving circuit receives through the laser light reflected echoed signal, and amplifying circuit, moment discriminator circuit are handled the laser echo signal that receives, and send into time interval measuring circuit to the signal of handling well then; Time interval measuring circuit also respectively with the emission coefficient circuit in pulse producer link to each other with control system circuit control chip; The signal that the laser pulse that the received pulse generator sends begins to send; And signal and echoed signal are carried out time interval measurement according to this, send the time interval parameter of being surveyed to control chip and finally handle.

Further, said laser instrument is 850 ~ 950nm, dutycycle < 0.1% impulse semiconductor laser for the optical maser wavelength that produces.

The work of each system of the control chip in the control system circuit (ECU) major control and the later stage computing of signal, processing, realize various functions according to result and the software that presets; And sending display module to show the result; Also, realize functions such as system interlink through communication interface and miscellaneous equipment communication.Emission coefficient is mainly used in the emission laser signal, and wherein the semiconductor laser need of work needs fast switching driving circuit to drive than higher threshold current, and the switch driving circuit switching signal provides the high-speed narrow pulse signal by pulse producer.Receiving system mainly is to receive laser echo signal and signal Processing, and signal is specifically received by receiving circuit and converts electric signal to, in amplifying circuit, amplifies then, shaping and filtering; Discriminator circuit provides time measuring unit required termination signal according to handling the back echo signal constantly; It is the initial moment with transponder pulse then at the high precision time interval measurement circuit; With the echoed signal is the terminal point moment; Measure both mistimings, confirm the time interval, and these time interval data are input in the control chip handle.

A kind of method that realizes vehicle-mounted four line laser radar systems comprises the steps:

(a) control circuit by system provides signal controlling emission coefficient emission laser pulse, transmits the signal that laser pulse begins to send to receiving system simultaneously;

(b) emission coefficient is launched laser by 4 laser instruments that are arranged in row by different angles simultaneously;

(c) 4 laser instruments are arranged on the motor driving shaft, and receive motor-driven to be rotated scanning, form four line laser radars and scan simultaneously;

(d) laser instrument is electrically connected through mercury slip ring and external circuit, and the movable end of mercury slip ring is connected with motor driving shaft, rotates with driving shaft with laser instrument;

(e) by optical system emitted laser is collimated to filter with shaping and to the laser-bounce echo and focus on to handle;

(f) the laser-bounce echoed signal after optical system is handled by receiving system to receiving, be converted into amplify behind the electric signal, shaping, filtering and carry out moment discriminating; Adopt the constant ratio discrimination method, the moment contrast with the pulse laser of receiving begins to send signal obtains the laser flying time, and it is sent into control system;

(g) control system obtains distance, orientation, the size of to be detected target according to laser pulse ranging according to the laser pulse ranging computing according to the light velocity and laser flying time, and combines this vehicle speed to calculate the movement velocity of target; Control system combines embedded software to carry out driver assistance according to operation result;

(h) vehicle-mounted four line laser radars are installed in the centre position of automobile headstock front end.

 

The invention has the beneficial effects as follows:

1, it is little to adopt semiconductor laser to make system have a volume, and precision is high, the characteristics of good stability.

2, adopt four line lasers to scan simultaneously, the scanning broad covered area, maximum detectable range can reach 200m, and resolution can reach 10cm, can effectively prevent the disappearance of detection of obstacles.

3, because the electric connector that the mercury slip ring is a compact conformation, life-span length, good stability, reliability is high, during high speed rotating scanning, scanning system can be because of it produce the noise noise, and the signal of transmission is undistorted; Scanning system of the present invention is littler with respect to the scanning system volume of rotating prism structure, and system performance is better.

4, four linear scanning systems disclosed by the invention, 3 D scanning system is simple in structure relatively, cost is low, realization is easy; A single relatively linear scanning system precision improves, false alarm rate is little.

5, system is except that having range finding, speed measuring function; In conjunction with software function; Also help expanded functions such as being integrated in detection of obstacles, anti-collision warning, spacing maintenance, pedestrian protecting, automatic cruising, lane departure warning, automatic emergency brake; Further alleviate driver's labour intensity, effectively reduce the quantity and the cost of automobile assistant driving system simultaneously.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention and useful technique effect thereof are further elaborated, wherein:

Fig. 1 is a line laser radar one-line scanning design sketch;

Fig. 2 is four line laser radar scanning design sketchs;

The laser beam synoptic diagram that laser instrument sent when Fig. 3 was a line laser radar scanning;

4 laser beam synoptic diagram that laser instrument sends when Fig. 4 is four line laser radar scannings.

Fig. 5 is the scanning system structural drawing of four line laser radars.

Fig. 6 is system architecture of the present invention and schematic block circuit diagram.

Fig. 7 is the installation site synoptic diagram of four line laser radar systems of the present invention on automobile.

Embodiment

Referring to Fig. 4 ~ Fig. 6, vehicle-mounted four line laser radar systems mainly are made up ofelectric power system 11,control system 10,emission coefficient 12, receivingsystem 15,optical system 14 andscanning system 13; Power module in theelectric power system 11 provides required power supply to each system;Control system 10control emission coefficients 12 are sent laser, through 14 pairs of laser of optical system collimate with shaping after, laser is met target object and is reflected; Afteroptical system 14 filters; By receivingsystem 15 reception reflection echo signals and after carrying out a series of processing, feed back tocontrol system 10, carry out calculation process bycontrol system 10; Saidemission coefficient 12 is by 4 laser instrument emission laser; Scanning system comprises motor 54 andmercury slip ring 50; It is characterized in that said 4laser instruments 53 are arranged onmotor driving shaft 55 connections and driven by motor 54, drive laser instrument and be rotated scanning, form four line laser radar scannings;Laser instrument 53 is connected with the terminals ofmercury slip ring 50movable ends 52, and thismovable end 52 is connected withmotor driving shaft 55, rotates withdriving shaft 55 withlaser instrument 53; 51 fixed installations ofslip ring 50 stiff ends, its terminals link to each other with driving circuit through wire harness 57.Certainly, laser instrument also can be arranged on other place, also can rotate with this movable end as long as be arranged onmercury slip ring 50movable ends 52 the same sides.

As improvement, said 4laser instruments 53 homeotropic alignment onmotor driving shaft 55 becomes row, and its optical axis forms different angles with surface level, so just can on a plurality of, scan simultaneously.The laser beam synoptic diagram that 4 laser instruments send during scanning is as shown in Figure 4, and the scanning effect is as shown in Figure 2.

Preferably, said motor 54 is a dc steppermotor.Scanning system 13 is mainly accomplished by dc stepper motor control, and for satisfying the running car requirement, sweep frequency is 15 ~ 30Hz, further is preferably 20Hz.

Usually, four line laser radar systems disclosed by the invention are installed in automobile headstock front end centre position, like Fig. 4 and shown in Figure 7, can make four line laser radar systems have the effective scanning scope of broad like this, for control system provides accurate target information.

Like Fig. 5 and shown in Figure 6, realize the circuit of vehicle-mounted four line laser radar systems, comprise control system circuit, emission coefficient circuit, scanning system circuit, receiving system circuit, electric power system circuit; Wherein the electric power system circuit includes the power module to each circuit system power supply; It is characterized in that: said control system circuit comprises control chip (ECU) and display module that is connected with control chip respectively and communication interface, and the display module displaying contents is controlled by control chip, and control chip is through communication interface and external communication; Said emission coefficient comprises pulse producer, switch driving circuit, thelaser instrument 53 that links to each other successively, and pulse producer links to each other with control system circuit control chip, and controlled by it; Pulse producer provides signal drive signal to switch driving circuit, drives 53 work of 4 laser instruments by switch driving circuit; Scanning system circuit comprisesmercury slip ring 50 and motor 54, andmercury slip ring 50stiff ends 51 are electrically connected through terminals and driving circuit; Said 4laser instruments 53 are arranged on themotor driving shaft 55, by being rotated scanning withmotor driving shaft 55, form four line laser radar scannings with themovable end 52 ofmercury ring 50;Laser instrument 53 is electrically connected through the terminals and themercury slip ring 50 of mercury slip ringmovable end 52; Said receiving system circuit mainly is made up of the bias circuit that links to each other successively, receiving circuit, amplifying circuit, moment discriminator circuit, time interval measuring circuit; Bias circuit is that receiving circuit provides required bias voltage, and receiving circuit receives through the laser light reflected echoed signal, and amplifying circuit, moment discriminator circuit are handled the laser echo signal that receives, and send into time interval measuring circuit to the signal of handling well then; Time interval measuring circuit also respectively with the emission coefficient circuit in pulse producer link to each other with control system circuit control chip; The signal that the laser pulse that the received pulse generator sends begins to send; And signal and echoed signal are carried out time interval measurement according to this, send the time interval parameter of being surveyed to control chip and finally handle.

Preferably, saidlaser instrument 53 is 850 ~ 950nm, dutycycle < 0.1% impulse semiconductor laser for the optical maser wavelength that produces.Be preferably the SPL LL series of pulses semiconductor laser of the OSRAM company production of Germany.

The main switching device of said switch driving circuit is preferably the EL7041C that Elantec company produces.

Said receiving circuit main devices is that the internal current gain is preferably 10 ~ 100 times APD avalanche diode.The APD avalanche diode has very high gain output, is beneficial to the more weak echoed signal of receiving intensity more.

The APD avalanche diode utilizes the directed movement of photo-generated carrier in highfield to produce avalanche effect to obtain the photocurrent gain.When reverse voltage continues to increase, can reach 100,000 multiplication benefits, (common 100-300V) internal currents gain can reach 10-100 efficiency-timed fruits under suitable bias voltage.APD works required bias voltage than higher, thus need bias control circuit provide bias voltage circuit to drive, and to guarantee the bandwidth and the response speed of receiving circuit.

Because target object is far and near different, the laser echo signal power that receiving circuit receives changes big, and the echoed signal fluctuation range of exporting in the receiving circuit is bigger; Undistorted for confirming signal; The present invention adopts controlled gain amplifying circuit, can reduce error like this, makes measurement more accurate.

Discriminator circuit mainly is that the signal of amplifying circuit is handled constantly, and for time measuring unit provides required termination signal, its performance has directly influenced the precision of system.The present invention adopts the constant ratio discrimination method, to reduce changing the error of bringing by signal amplitude.It specifically mainly is made up of delay circuit, attenuator circuit, high-speed comparator circuit, threshold values comparator circuit.

Said time figure conversion chip is preferably split-second precision digital conversion chip TDC-GP2 that German ACAM company produces.The measurement in the time interval directly has influence on the precision of system, just needs time precision to reach the 100ps rank as reaching the centimetre-sized precision, and the precision of TDC-GP2 can reach 65ps, and the circuit simple and stable of forming.

System's operational process is following: behind the system initialization, each system gets into SBR.Under control chip control, then pulse producer produces start pulse signal CS drives laser instrument and sends laser pulse; When producing triggering level, send laser pulse and begin to send signal entry time interval measurement circuit, signal picks up counting TDC-GP2 chip to start with.Laser pulse is received by receiving circuit behind the object reflected back; And change light signal into electric signal; Signal is sent into TDC-GP2 chip after amplifying circuit is amplified into discriminator circuit processing constantly makes it stop timing; TDC-GP2 sheet calculates the time interval and sends into control chip (ECU) and handle, and so far once range finding is accomplished.Scanning system uninterruptedly scans, and ranging information is imported control system into each time, and control system shows corresponding data according to gained information, and Control of Automobile is made corresponding actions.

With reference to figure 5 ~ Fig. 7, a kind of method that realizes vehicle-mounted four line laser radar systems comprises the steps:

(a)control system 10 by system provides the signal controllingemission coefficient 12 emission laser pulses, transmits the signal that laser pulse begins to send to receivingsystem 15 simultaneously;

(b)emission coefficient 12 is launched laser by 4laser instruments 53 that are arranged in row by different angles simultaneously;

(c) 4laser instruments 53 are arranged on themotor driving shaft 55, and receive motor 54 drivings to be rotated scanning, form four line laser radars and scan simultaneously;

(d)laser instrument 53 is electrically connected throughmercury slip ring 50 and external circuit, and themovable end 52 of mercury slip ring is connected with motor driving shaft, rotates withdriving shaft 55 with laser instrument;

(e) collimate and shaping by 14 pairs of emitted laser of optical system, and the laser-bounce echo filtered focus on to handle;

(f) the laser-bounce echoed signal afteroptical system 14 is handled is received by 15 pairs of receiving systems, be converted into amplify behind the electric signal, shaping, filtering and carry out moment discriminating; Adopt the constant ratio discrimination method, the moment contrast with the pulse laser of receiving begins to send signal obtains the laser flying time, and it is sent intocontrol system 10;

(g)control system 10 obtains distance, orientation, the size of to be detected target according to laser pulse ranging according to the laser pulse ranging computing according to the light velocity and laser flying time, and combines this vehicle speed to calculate the movement velocity of target;Control system 10 combines embedded software to carry out driver assistance according to operation result;

(h) vehicle-mounted four line laser radars are installed in the centre position of automobile headstock front end.

Said laser pulse ranging is to launch a string laser pulse through laser instrument, and laser pulse aloft flies and when running into barrier, reflects the entering receiver, thereby measures the distance that the skyborne flight time of laser pulse calculates barrier.The velocity of propagation of laser is 300,000 thousand metre per second (m/s)s, and the speed that the laser pulse flight time multiply by laser is exactly the round distance to barrier, divided by 2 can obtain barrier distance.

It is exactly to measure spacing that the present invention the most simply uses; Or according to self speed of a motor vehicle in interval time with the speed of mobile things such as the respective measure of the change front truck of front truck, pedestrian; These functions can be used for maintaining safe distance automatically when being equipped with automatic cruising (ACC) function; Alleviating driver's driving intensity, safety and comfort more during driving.Also can be used for the early warning of barrier, auxiliary be implemented in collision and can take emergency brake when inevitable, discharge the safety that people in the car is protected in measure such as air bag in advance.But also can come the inspection vehicle diatom to be used for lane departure warning to the different reflectivity of laser according to track and lane line; In addition; Laser radar can combine curb, isolation strip and the barrier of road both sides to wait to assist to realize this function; Make detection more accurate, reduce the collision that meets accident because of deviation, further improve traffic safety.

The present invention is not constituted any restriction according to above-mentioned instructions and specific embodiment; The embodiment that discloses and describe above the present invention is not limited to; To modifications more of the present invention and distortion, also should fall in the protection domain of claim of the present invention.

Claims (10)

1. vehicle-mounted four line laser radar systems mainly are made up of electric power system, control system, emission coefficient, receiving system, optical system and scanning system; Electric power system provides power supply to each system; Control system control emission coefficient is sent laser, and laser is met target object and reflected after handling through optical system; Again after optical system is handled; By receiving system reception reflection echo signal and after carrying out a series of processing, feed back to control system, carry out calculation process by control system; Said emission coefficient is by 4 laser instrument emission laser, and scanning system comprises motor and mercury slip ring, it is characterized in that: said 4 laser instruments are arranged on the motor driving shaft, and receive motor-driven to be rotated scanning, form four line laser radar scannings; Laser instrument is electrically connected through mercury slip ring and external circuit, and the movable end of mercury slip ring is connected with motor driving shaft, rotates with driving shaft with laser instrument.

2. vehicle-mounted four line laser radar systems according to claim 1 is characterized in that: said 4 laser instruments homeotropic alignment on motor driving shaft becomes row, and its optical axis forms different angles with surface level.

3. vehicle-mounted four line laser radar systems according to claim 1 and 2, it is characterized in that: said motor is a dc stepper motor.

4. realize the circuit of the described vehicle-mounted four line laser radar systems of claim 1, comprise control system circuit, emission coefficient circuit, scanning system circuit, receiving system circuit, electric power system circuit; Wherein the electric power system circuit includes the power module to each circuit system power supply; It is characterized in that:

Said control system circuit comprises control chip and display module that is connected with control chip respectively and communication interface, and the display module displaying contents is controlled by control chip, and control chip is through communication interface and external communication;

Said emission coefficient comprises pulse producer, switch driving circuit, the laser instrument that links to each other successively, and pulse producer links to each other with control system circuit control chip, and controlled by it; Pulse producer provides signal drive signal to switch driving circuit, drives 4 laser works by switch driving circuit;

Scanning system circuit comprises motor and mercury slip ring, and mercury slip ring stiff end is electrically connected through terminals and driving circuit; Said 4 laser instruments are arranged on the motor driving shaft, by being rotated scanning with motor driving shaft, form four line laser radar scannings with the movable end of mercury ring; Laser instrument is electrically connected through the terminals and the mercury slip ring of mercury slip ring movable end;

Said receiving system circuit mainly is made up of the bias circuit that links to each other successively, receiving circuit, amplifying circuit, moment discriminator circuit, time interval measuring circuit; Bias circuit is that receiving circuit provides required bias voltage, and receiving circuit receives through the laser light reflected echoed signal, and amplifying circuit, moment discriminator circuit are handled the laser echo signal that receives, and send into time interval measuring circuit to the signal of handling well then; Time interval measuring circuit also respectively with the emission coefficient circuit in pulse producer link to each other with control system circuit control chip; The signal that the laser pulse that the received pulse generator sends begins to send; And signal and echoed signal are carried out time interval measurement according to this, send the time interval parameter of being surveyed to control chip and finally handle.

5. circuit according to claim 4 is characterized in that: said laser instrument is 850 ~ 950nm, dutycycle < 0.1% impulse semiconductor laser for the optical maser wavelength that produces.

6. circuit according to claim 5 is characterized in that: said impulse semiconductor laser is the SPL LL series of pulses semiconductor laser of the OSRAM company production of Germany.

7. circuit according to claim 4 is characterized in that: the EL7041C that the main switching device of said switch driving circuit is produced for Elantec company.

8. circuit according to claim 4 is characterized in that: said receiving circuit receiving device is that the internal current gain is 10 ~ 100 times an APD avalanche diode.

9. circuit according to claim 4 is characterized in that: said time figure conversion chip is split-second precision digital conversion chip TDC-GP2 that German ACAM company produces.

10. realize the method for the described vehicle-mounted four line laser radar systems of claim 1, comprise the steps:

A. the control circuit by system provides signal controlling emission coefficient emission laser pulse, transmits the signal that laser pulse begins to send to receiving system simultaneously;

B. emission coefficient is launched laser by 4 laser instruments that are arranged in row by different angles simultaneously;

C.4 a laser instrument is arranged on the motor driving shaft, and receives motor-driven to be rotated scanning, forms four line laser radars and scans simultaneously;

D. laser instrument is electrically connected through mercury slip ring and external circuit, and the movable end of mercury slip ring is connected with motor driving shaft, rotates with driving shaft with laser instrument;

E. by optical system emitted laser is collimated to filter with shaping and to the laser-bounce echo and focus on to handle;

F. the laser-bounce echoed signal after optical system is handled by receiving system to receiving, be converted into amplify behind the electric signal, shaping, filtering and carry out moment discriminating; Adopt the constant ratio discrimination method, the moment contrast with the pulse laser of receiving begins to send signal obtains the laser flying time, and it is sent into control system;

G. control system obtains distance, orientation, the size of to be detected target according to laser pulse ranging according to the laser pulse ranging computing according to the light velocity and laser flying time, and combines this vehicle speed to calculate the movement velocity of target; Control system combines embedded software to carry out driver assistance according to operation result;

H. vehicle-mounted four line laser radars are installed in the centre position of automobile headstock front end.

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